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CO «= oF fee [A BACK ce ue’ Pe Sa desta. FS MA Sune CATECHISM for CANDIDATES FOR RATINGS I 6 INCH GUN compiled by MARK LORIN ARELAND Captain, Coast Artillery Corps, U. S. Army, and ROBERT HENRY LEE, Second Lieutenant, Coast Artillery Corps, U.S. Army. 1y13. TH ESIS PREPAC This work was originally undertaken for the instruction of the 88th Company,Coaast Artillery Corps,during the winter of 19138-1913 at which time the comnilers were the officers on duty with that company. The amount of labor involved in gettin, the information together and the very general interest taken in the work¥bv the enlisted men suggested the offering of the vaner to the Journal of the U.S.Art- illery for publication under the same condition as the Gunners! Instruction pamrhlets,the sale to be without profit to the comrilers. The inspiration for this work has come from the men who were eager to learn and comnrete for these snecialized ynositions when the way was opened for them to acquire thé .2% to incliie,when it scene , | ad % in a vsareral way the scone of no syllazus of these exanminat— 3 + 3 For the cunners'examirnations oO QD mace the catecnism = 3 Feasible, information soneearnins other materiel in cruer tnut the cateacn? 5% mists 28 uted in ecennranies atricned 40 cthar wouela and calibers until auch time as the satechian nay be adanted by the servic? £9 aacth alazya of materiel. The real standard of requiire@itris on those oxaninations will be detearmined.ags cefora ey ensh cenpanyv conmangdor., There ia seliom reasonable sround for chiection to tie candic.te oeinz too atl) in®forred, The cornrilers have tnerefore preferred to follow thea exanrle of thea Surreral Txstruction ramvhlets when tney excaried the scecsea of the svllabus rts iribed for them,ard to err in the direction cf enllecstinzs t39 inuch ratier than too littls information. < ’ : v Santain Coast Artillery Corre," 7.-. Robt H. dee, end Lieutenant, Coast Artillery Corns ,".5.4. This pater wa3 Tirs3st aguomitted to tne Michizan Agricultural College as a technical parer,or tiasis3,®or the vost -craduate desree of mechanical angineer. The conditions of aseantarce of the degrea require t°e annenuing of tris stateuant to show its original puolicaticn as a tne3is. Live EEA Ld Cantain Goast Artillery Corns, T.8.A. CONTENTS, G—--INAN at, ee ee ee ee CIN CUPANDPR and CN DOINTYE, IT Tefinitions,©.A.0D.R. II Gun and carriage. . (a) Nomenclature,vurpose,and action of several rarts. (db) Packing stuffing boxes and cleaning recoil cvlinders. 30 (c) Adjustsent of-- Quadrant elevation device,asignt standard,throttlins valve, gas-check vad,elevating zear,grease cuns,and firing mecnanis3mn. IZ (ad) Care and wreservation, including care of hand counterweichts, Oiling,and vcainting. — III Powaers,vrojectiles,fuses.and primers, Ventilation of magazines. ~— +2} Blending nowder and vrevaration of novider charges. — (o) Filling and fusing projectiles. — bat Painting vrojectiles. — e) Care of empty cartridze cases and vriner bodies. — IV Preparations for syervice or subcaliber practice. —_ VY Service of the niece. — (a) Duties of each meuoer of the gun section urder all conditions. annmpy VI Precautions for safety at the battery. VilI.Fire-control syste. (a) Seneral knowledge o* that in use at the battery. Sb (o>) Duties cf range keener; object and use of time range board.s—m VIIT.Pointing. fa) Methods of nointing and pointing tests. 37 (>) The telescovic signt (the quadrant for mortars). 4l (c) Emergency system and salvo roints. 43 (d) Bore sighting and orientation. IX Regulations governing service and subcaliber practice .so far as tne affect the service at the emolacsceuents. — X “ounting and dismounting guns and carriages. — XI Characteristic features ot the several clas3es of War ships, general knowledge cf local shixring,of channels leading to the haroor,ara oF ranses to zrominent fixed obdjects in the field ct fire of the Dattery. SF | TI. IIft. IV. Il. Tit. PLOTTER. ~4 Definitions C.A.D.R. Fire-control system. (a) Detailed knowledge .of system employed at the (>) Indication and identification of tars sets. (c) Duties of each member of the ranze section under all conditions. ; (qd) Emergency system and salvo pf Pire-control arnaratus. (a) A detailed knowledge of adjustuent and use of all fire- --ntrol anparatus used in the plotting roon. Elementary gunnery. (a) Explanation of the several corrections to be annlied to the ovserved range to cbtain the corrected range. fo) Fffect on the flicht of the vrojectile of variations in the density of the air; the direction and velocity of the wind. battery. Cints. (c) Use of trial shots and arvlication of duta obtained from them (sroodlem). Preparation of target-vractice records. ORSERVER(FIRST AND SFCOND CLASS). Definitions C.A..N. Fire-control system. (a) Detailed description of that in use at tre (pb) Indication and identification of targets. (c) Emergency system and salvo points. Fire-control avparatus. (a) A detailed knowledge of adjustment and use of all observing instrunents ana range finders in use at the battery. (o) Use of the telephone. Observer's test C.A.D.4. Characteristic features of the several classes of war ships,zgeneral knowlecze of local shinping,of channels leading to the harbor,and of ranzes to prominent fixed objects in the field of fire of the battery. Cg attex ry . PAGE PS- 7¢ 73 116 /2/ 122 13/ 13 4- 436 437 3F APCPRNYNTOWS , Pxtracts fron Drill regulations, “sast Artillery,1eCs, Data for Guns and Mortars and their Carria: 2s. The Telerhone. List of Crdnance VPanvhlets for leferance, Instructions for Loading Projectiles with Fxplosive ©. a R aon « TN 4 mo r , ww : A r S-inch Gun,Disa- pearing Carria Oo Naytical and “aval aafinitions. oe er ee a a a PASE, 4 1F2 173 174 IVF 17 @ 177 1735 GUN COMSANDRR OR STN POINTER. I.Definitions,C.A.).R. See questions indicated in "GUN COMMANDER OR GUN POINTER" ag column in anpendix A. Elomentry gunnery definitiona are illustrated on Elemen Gunnery and Warships diagram under Plotter IV Elementry Gunnery (a) Explanation of the several vorrections to be applied to the observed range to obtain the corrected range,facing page /Z3 . GUN COM.ANDE: AND GUN POIN ER IT GUN AND CARRIAGE (uvhe answers to the following questions on gun and carriage are for 6 inch rapid fire gun Model R897 }*.and disappearing carria;s‘e Model 1898 for 6 inch gun.See Ord.pamplet No.168o0 on disappearing carriage for 6 inch gun,and Ord. pamnplet.No.1765 on 5 inch and 6 inch rapid fire guns.) (a) Nomencaature, purpose and action of several parts. 1.Q.0f what metal and in how many parts is the base ring made: A.It is made in one piece of cast iron, 2.Q.What purpose does the base ring serve? A.It serves as a fixed level base for the carriage; its upper surface provides the lower path for the conical rollers; and an annular projection from it serves as the female part of the pintle. It also serves to hold the traversing rack in place. 3.Q.How is the base ring leveled before setting it in the cement of the foundation? A.By means of 12 bronze leveling screws in the base ring. Steel plates are provided in the concrete beneath the screws for the screws to bear against in the process of leveling. 4.Q.How is the base ring secured to the foundation? A.By 12 1.75 inch foundation bolts set in the concrete, §.Q.0f what metal is the azimuth circle made? A.Brass. 6.Q.How is it held in place? A.It is attached to the top of the pintle of the base ring by counter sunk screvs. 7.Q.How is it graduated?! A.In degrees. Tno numbers are added after the carriage is mounted in its exiplacement. 8.Q.How is the ezimuth circle read? A.By means of the azimuth pointer and subscale fastened to the racer on the left sido where the top of the racer has an opening exposing the circle, 9,.Q.0f what metal and in how many pieces is the racer made: A.It is made of cast stecl in one piece, 10.Q.\‘hat purpose does tne racer server A.It supports the two chassis. Qn its underside is formed the upper roller path, .& cylindricel projection 11/4 inch thick from its underside forms ine male part of the pintle. It supports the sight standard,dust guard and traversing mechanism. 11,Q.Describe the traversing rollers and distance ring? How many rollers are there: A.shere are 2C rollers, They are made of forged stecl with a trunnion at each enc. On the inner end of each is a flanse to suide the roller on its path. The diameter of the inier end is less than that of the outcr end. ‘the distance rings are united and stiffened by 10 separators. The roller trunnions fit into the rinzs at equal spaces In this way the rings keep the rollers at equal distances and prevent their jamming together. 12.Q.Explain why the traversing rollers are cone-shaped. A.suhe circumfcrence of the outer edge of the rolle: path is larger than that of the inner edse, Therefore where the cun is truversod the inzcr enc of the roller has a smaller distance to travel over than tie outer end has. Hence the circumference of the imner enc of the roller is made smaller than tnat of the outer end to correspond to the smaller distance it traverses. So,for any point between the inner and outer ends of the roller,the circumference of the roller at that point corresponds to the distance that point has to traverse. The center of the base rine is the only point in it which does not have any rotary motion when the carrkage ia traversed. It is theres fore the apex or point of the cone-shaped surface of each roller,if the surface were extended sufficiently. 13.Q.Describe the dust guard? A.uthe dust guard is composed of four sections. ‘the sections are made of steel and are bolted at the top to the racer, he row of bolts at the bottom secures the steel and felt cloth strips which prevent dust from entering at the bottom and accumulating on the roller and paths. 14.Q.What are the chassis? A.The two chassis,united near their middle by a transom,form the structure which rests upon the racer and supports the top carriage. 15.Q.0f what metal are they made? A.ihe chassis are made of cast iron and the transom of cast steel. 9 16.Q.Give all the purposes for which the chassis serve A.l.10 support the top carriage. &.10p surfaces form recoil roller path,also called the chassis rail ‘sometimes, 3.Crossheadgguides are cast on them. 4.Support ends of piston rods. 9eSupport elevating pinion shaft,elevating worm wheel bracket elevating rack guides. 6.Support retracting mechanism, 7eoupport tripping sear. 8.Support recoil buffers, 17.Q.What is the slope of the recoil roller paths and what is the reason for this slope? A.The recoil roller paths slope one degree to the front,making it easier for the counter-weight to force the gun into battery. 18.Q.0¢ what does the top carriage consist? A. Two sides frames and two recoil cylinders united by a transom. 19.Q.How is the top carriage made and of what metal? Ashe top carriage is cast in one piece,the metal beins gun iron. 20.Q.Describe the purpose of the top carriage? A.The side frames contain the recoil cylinders and the beds for the gun lever axle. The rec@il cylinders hold the oil and the piston heads,the main parts in the control of the energy of recoil after discharge. 21.Q.Describe the action of the top carriage,gun levers and counter-weight during counter recoil and recoil? A.During counter recoii .s the counter-weight hung on suspension rods to the cross heac ,7escends it draws downward the front ends of the gun levers. this movement causes the gun lever axles to be drawn to the front,bringing the top carriage with it. The top carriage moves forward over the live roller train on the roller path of each chassis,the top carriage moving twice as fast and twice as far.in a forward direction as do the centers of the rollers..che gun lever axles being the pivot,as the cross héad pins at the front end of the levers go downward the rear ends must move upward. The upward and for- ward motions of the rear ends of the levers catry the gun into the firing position. Mmrring recoil the motion of thre different parts is opposite to that in counter recoil. ane force which produces recoil is povrer sressure which not only moves the projectile forwara but also causes the sun to kick backward,or recoil,w:en fired. The force which produces counter recoil is that due to the weicht of the counter weisnt being Sreater than that of the varts which nave to be moved when the gun foes into battery. : 22.Q-Describe tre recoil :oller frames,thne rec il rollers and their action: A.Each frame consists of two side pieces and tvio end pieces formins a rec- tan;le. The side pieces have bronze—bushed holes for the roller trunnions to fit into. she frame serves to hold the rollers in place and cause them to act together. Each fr:me contains 14 rolle:s,fThe rollers are of forged steel and have a flanse on each end to cuide them on the path. 23.Q.nat devives insure the movexent of the ton carriace being straight to : the front or rear? Asthe cylinder guides which project dovnvard from the cylincers on both sides of the chassis rails and the flanres on the rollers. 2%eQ."nen is tne gun fully in battery? Aewnen the forward projections on the top carriage are azainst the stons on the chassis crossheac cuide frames. 25.Q.0f what metal are the gun levers made? A.Cast steel. 26.Q.At what point and by what are they connected? A.A little below their midcle by the forged steel gun lever axle. 27 eQeHow is the axle secured to the levers? A.xeyed to them. 28.Q.For what do the projecting ends of the axle serve: A.shey serve as trunnions for the gun levers, ishey rest in bronze bushed axle beds in the side frames of the top carriage,and are secured therein by bronze bushed axle caps. 29.Q.What is the crosshead ? A.that mass of metal which forms the connection between the gun levers and the counter-weight. 30,Q.Why is the connection between crosshead and gun levers made by cylindrical pins passing through cylindrical holes in the ends of the levers. A.Because when the counter-weight rises or descends the levers mist be free to rotate about their lower ends. 31.Q.Why do the crosshead and counter weight move in a vertical direction‘ A.Be cause the cross head clips on the cross head fit around the cross head guides on the inside of the chassis and the guides being vertical compel the cross head to move vertically. 32.Q.In what direction would the counter weight move if there were no guides (a) during recoil (b) during counter recoil. A.\a 33.Q.De A.In ) upward and toward the front (b) downward and toward the rear. scribe the action of the tripping gear giving the names of the different parts? order to trip the gun one or both of the tripping levers mst be raised until they are latched. she tripping gear on the two sides are identical. Lifting the tripping lever upward about its fulcrum draws the tripping rod toward the rear. This movement pulls the upper end of the tripping shaft lever to the rear,this rotates the tripping shaft which throws both the right and left tripping arms against their respective pawls tripping the latter, The pawls having been withdrawn from the crosshead racks,the excess in weight of the counter weight over the weights of the other moving parts causes the counter weight to fall and the gun to rise into the firing or "in battery"position. 34.Q.Describe the action of the tripping safety mechanism. A.It consists of the following parts duplicated for each side ia tripping safety latch and spring;a dog on the side of the crosshead near the upper end of the rack;cone-shaped catch on the tripping roc having the large end forward. The tripping safety latch spring holds the latch with the upper end projecting outward thm a slit in the chassis close to the tripping rod and the lower end projecting inward in the path of the dog. When the tripping lever is raised the tripping rod carries the catch past the upper end o: the latch forcing the latter in against its spring. As soon as the catch passes to the rear the spring throws the safety latch in front of the catch thus holding the rod back with the pawls dis- engaged until the cross head descends and the rack teeth are clear of the pawls by about a foot. The dog then forces the lower end of the safety latch outward which draws the upper end inward and allows the rod and catch to move forward returning the pawls to the position from which they are ready to engage the crosshead when it rises, For precautions to be observed in trippins,see Duties of No.9? under Service of the Piece, Page . 35.QHow is the counter-weicht supported? A.The layers of counter-weight rest upon the bottom plate. Two suspension rods extend from the bottom plate to the crosshead and support the entire counter-weight. 36.Q.eHOow many hand weights are furnished with each carriage and what is their total weight? A.16 handweights weighing in all about 1,000 lbs. 37.Q.What is the purpose of the handweights: A.by adding handweights the gun can be made to go into battery more quickly;or if it fails to go fully into battery,usually enough hand weights may be added to force it fully into battery. If the gun foes into battery too quickly,causing the top carriage to bump against the stops,enough handweights may be removed to cause the gun to go into battery properly. 38.Q.what is the total amount of counter-weight furnished with the carriage: A.About 19,000 lbs.of lead. The bottom plate, crosshead and suspension rods weigh about 3000 pounds more, 39.Q.Name and locate all the parts of the recoil system and describe the purpose and action of each part? Ael.Iwo recoil cylinders,formed in the top carriase casting. The cylinders contain the hydroléne oil. Each nas on the inside two throttling bars. As the top carriage moves toward the rear during recoil,and toward the front during counter recoil,the oil is compressed in that part of the cylinders betveen the piston heads and the ends of the cylincers approachins the piston heads and is forced thru the various openings to the opposite side of the piston heads. Most of the force of recoil and of counter recoil are spent in forcing the oil thru some of these openings. 2. lwo piston rods with a piston head forged solid with each. The rods are secured and held stationary by the chassis in front and the piston rodbrackets in rear. Each piston head has two slots in which the throttling bars work. 3.4 throttling bars,2 bolted to opposite sides of each cylinder . The bars have the same width throughout the length but have a varing thickness, the reason for which is as follows: she amount of pressure on the oil in the cylinders dencnds upon tio things,namely,the velocity of recoil of tne cylinders and the size of the opening for the passage of the oil. she greatcr the velocity of recoil the craater the pressure, she smaller the size of the opening for the passage of the oil the creater the pressure. If the throttling bars are given a varying thickness bearing a certain relation to the velocities with which the different points of the bar move over the piston it is evident that the oil pressure may be kept constant and the metal of the cylinder \ill not be stressed too much. To obtain the constant pressure,when the velocity; of recoil is the greutest the thickness of the throttling bar is the least civinz the greatest opening for the oil.As tne velocity of recoil decreases the thickness of the bar increases causin;; the opening to decrease. Therefore the bars are so made that the rear ends are the thinnest parts and the thickness increases toward the front, \ If this were not done the cylinders would have to be built stron, enough to stand the maximum pressure,in spite of the fact that for the greater portion of the time of recoil,the oil pressure would be but a small fraction of this maximum pressure. 4,Equalizing pipes. They connect the front end of the cylinders, allowing the oil to flow from one cylinder to the other,and thereby equalizing the pressure in the cylinders. »eConnecting pipe. It connects the equalizing pipes with the throttling pipes,allowing the oil to flow from one end of the cylinders to the other by way of the equalizing pipes,connecting pipes ana throttling pipes during recoil or in opposite direction during counter recoil. 6.shrottling pipes. shey connect the rear ends of the cylinders for the same purpose that the equalizing pipes connect the front ends. 7.Throttling valve. It regulates the recoil of the gun by varying the opening for the oil to pass thru in going from the connecting pipe to the throttling pipes. she valve can be adjusted to give openings varying by 0.0066 square inch from 0 to 0.2 square inch. whe graduations of the valve are stamped on top. There are eleven divisions numbered 0,-02,.04 etc up to 0.2 one half turn of the valve changes the opening 0.0066 square inch; a whole turn changes it twice 0.0006 or .O133 square inch: hence it takes 3 half turns to move from one numbered division to the next. ihe purpose of the throttling valve is to control the length of recoil. Read in this con..ction the ciseussion as to why it is safe but poor artillery practice to fire the cun ween the top carriage is as much as 2 inches out of the "in battery” position under Duties of No. 9 Service of the Piece, pare ° If the strensth of the cylinder walls were without limit it is evident that the recoilof the piecc could be taken up in a very short length of recoil by forcins the full quantity, of oil thru sev only one exc ll slot in tne piston. 90 also,if ‘tre one slot. occ ouce very Llarce the oil would meet with little .esistanc: in passins thiw the piston ane wre evlincerf would have to te very lon: end move a lonc cistunce to aisor> all of the enersy of recoil. Mechenical consiccrutions maxe 1% adviceble to have tyvo cllinccivs auc two slots in eac pictone Mow having Ceciced upon a reusonuble Lencth of recoil permittocd b. the size of his cacriave,ts cesioncr couputes the exuct sizes of Slot openin’s,or orificesywnich arc require at several points alone the var to absor> the desicned force of recoil of the mm. This force mc; however be exccecer hence the cesiener allows for this by making his orifices a little smaller. Whis final set of sizes would be satisfactory if there was some way of lettin, the oil get past the piston easier when light pressures shots were fired,that is,the recoil system still needs a reculator to make the length. ot recoil stay the same or nearly the same. shis is exactly the part the throttling valve plays. It is a by-pass so tnuat the battery comsander can,by adding a variable amount to tne size of tne orifices made bi the designer to take care of the heaviest pressure,make the length of recoil stay at the amount the designer intended within close limits. For convenience thc Lengvh of recoil is indicatcda by the number notch of the notch in the cross head racks at which the pawls come to rest, The proper notch for the 6 inch disappearins carriace model 1898 is the 19th. One whole tur o- the throttling valve changes the length of recoil by about two notches. (In printing omit underlined word and leave a blank) ny aot 8.Recoil buffers. whey are made of alternate layers of balsta anc steel and are supported on the chassis. Their purpose is to take up the shock of recoil in case the oil fails to check the recoil properly. hid 2 ° e 9 Ly e 3 40.Q.\shy are the fillings plugs about 30 from the top of ‘hc cylinders? A.So that it is impossible to fill Lr cylinceys withous leavin: an air 41.Q.i/ould any damue to the carriase occur if it were firec when say « spacefin the top of each one to make room for the oil when it expands due to hot weather,or to the heat of friction inside the cylinders durins firinc,and also to make up for the space occupied by the male part of the count r recoil buffcrs as explained unde: counter recoil system cclov. ” inches out of battery? “xplain. A.No. The fillin: plugs of the cylinders are purposely so located that it is impossible to completely fill them with oil. “hen in battery the piston head is in the rear (higher) end of the cylinder. All of the air in the cylinder is now over the piston head. At the instant that recoil begins that portion of the air in front of the piston head rushes to the rear. she recoilins parts,including the counter- weich},beins very heavy it requires about 3 to 5 inckes of movement to ‘build up’ the specd of the moving parts. whe throttling bar orifices (openings between the throttlins bar curved surface and the bottom of the piston head slot) are so large that throttling effect is neglisible for small to moderate velocities but increases to great proportions as the velocity of recoil increases. therefore little or no checking of the recoil occurs in the first two inches of the movement away from the stopping surfaces on the chassis cross head euide frames. the shortening of the length of recoil by firing when the top carriage 42.Qels is not fully in battery lessens of course the space in which the enercy of recoil can be absorbed by the throttling process. Fully counteracting this,within the limit of 2 inches under discussion,is the fact that the point of maximum velocity of recoil falls farther to the rear measured on the roller path,farther forward as measured by the position of the piston head on the throttling bar,hence for each successive position the velocity will be relatively greater for the same size of orifice,hence a more than proportionately creater throttling or energy absorbing effect. It is this principle which enables the designed length of recoil to take care of all usual variations in power pressures in successive charges with a given throttling valve setting. there any objection to firing with the top carriage not over 2 inches out of battery! A.From the standpoint of the ordnance engineer,No.See page 14,0.P,1686,1911. From the standpoint of the artilleryman,yes. See C.A.D.R.378, and Duties of No.9 under Service of the Piece, page ° 43.Q.Describe the counter-recoil buffers and their action? A.Each buffer consists of a male part on the piston rod against the rear face of the piston head ana the female part,a corresponding recess in the rear cylinder head, The male part is a cylinder in appearance but really has three tapers of varying steemess on its surface. When the top carriage is within about 4 inches of the stops of the chassis the female part on the rear cylinder head is just beginning to move over the male part. The oil pocketed in the female part can escape only thru the clearance space between the male and female parts. In carriages having a buffer valve some oil escapes from the pocket thru the buffer valve, ihe clearance at this stage between male and female part is large but as the female part moves over the male part toward the piston head the lighter tapers come into play and make the clearance smaller hence the oil pressure inside of the pocket higher. Thus the pressure on the pocketed oil is small when the velocity of the top carriage is high and as this pressure stops the top carriage it increases thus bringing the top carriage,counter weight and gun to a "cushion" stop without any hard blow agains$ the metal stops of the chassis. When the gun is fired,the recoiling parts gain their maximum velocity in the first few inches of movement of the top carr!:.zge. The femais parts of the counter recoil buffer is therefore quickly draw off of the male part,too quickly to allow the oil on the low pressure side (rear) of the piston head to fill the female part until it is wholly clear of the male part. During this instant there is probably less than ordinary atmospheric pressure (a partial vecuvm) in the pocket while the effect in the rear part of the main cylinder is that of suddenly adding the full volume of the metul of the male part. If the cylinder were entirely filled with oil,an almost incompressible substance, an enormous pressure would be created. If several cubic inches of air are always left in the cylinder due to the position of the filling plugs, this air will stand the compression due to expansion of oil from heat or to the above action of the recoil buffer without any high press- ure developing. 44.%eName all the parts or the elevating system ¢iving the purpose of each part? Aol,tlevating hand wheel, ty which a member of the gun section elevates and depresses the cun. @ Elevating hanc wheel shaft,which supports the elevating hance wheel. 3.Two clevatins bevel gears,one on the end of the elevatines hana wheel sraft and the other on the front end of the elevating worm shaft,mesnine tosetner. 4,ilevatincs worm shaft,coniecting elevatins hand wheel shaft with elevatin-~ pinion shaft. 5 wlevatins worm,on fear end of worm shaft,and clevating worm wheel near left end of elevating pinion shaft coniecting worm shaft with pinion shaft. | 6.2levatins pinion shaft,passing thru chassis and supporting the elevating pinions. 7.,1wo elevating pinicns whose tecth e. care in the tecth of the clevatine racks anc ruise anc lowor * 2 ra 8.uwo “cronze elevatins rack culices bolted to seuidine the racks. 9.Two elevagins racks which raise anc lower the lower crnd of the elevatine arm. lc. .tlevatine arm,consectins: clevatins band with racks. 11.2levetion disk (range drum) around its circumference is a white metal bana sraduated in yarcs for service and sub-caliber ranres. It is also craduated every © * +0 enable the battery comaancer to check the correctness of the location of the ranse pointer. The reading of the ranse scale is incicatec by the elevation pointer on the worm wheel bracket. she pointer is held in adjustment by two dowel pins. 12.flevatins maneuver hand whecl,by means of which the cun pointer may elevate and depress the fun. 13.The motion of the elevating maneuver hand wheel is transmitted thru the several puris in the following order: elevating maneuver hund wheel shaft,elevatins maneuver bevel »inion shaft and elevatine maneuver svaft. The bevel gear on the elevatine hand wheel shaft which meshes with tne bevel cear on the lowr end of the elevating mancuver snaft can be locked to the elevating hand wheel shaft by a clutch operated by a clutch handle,thereby throwing in the elevating maneuver sear for action, shis gearincs is seldom or never used pecause the gun will seldom or never »e fired by Case I from the sighting platform. CXSe t"-e cniascis,suprortine and 45.Q. what is the shape of the elevating racks and fuides? what is the reason for this shape? A.Hach is an are having the elevating arm as a radius and the center of the arc at the axes of the élevating band t:unnions. Thir arranzement permiis the cun being set to the proper range (elevation) while in the loadin: position vithout changing the height of the breech above the loading platform,since tne raising or lowering of the elevating racks to give the proper range setting does not move the elevating band trunnions. In gun batteries larger than o inch where the projectile is too neavy to be thrown into the gun by hand by one man any great change in height of breech results in delay until the height of the shot pan of the ammunition truck shot pan ean be adjusted to the new height. In the later carriages however the curved racks have been abandoned because of the expense of making them and because it has been found that the change in height of breech is not so large :.s to be important. 46.Q.\that is the maxi:um elevation and depression of the gun? How is the maximum depression assured? A.Maximum elevation is 15 ‘dpove horizoital,maximum depression is 5° below horizontal. ‘ A lug is cast on the rear part of each rack and two holes for stop bolts against which the lugs strike are drilled in each chassis near the upper end of the path of the elevating racks,since the racks are moving upwara when the gun is being depressed. Stop bolts are inserted in the upper set of holes when the concrete parapet is constructec to allow firing at »° depression and in the lower set of holes when the parapet is constructed to allow firing in positions not lower than horizontal. Batteries near sealevel co not necd to fire in do ression “cnce are built with riehcr parapets to cive creater protection to ~un, 6arriage, anc personnel, Moter:rre battery comiander will cause the one of the two next peractreprs Wiich does not appl, to his hatter, to be cancelled in all hooks pefore issue, whe parapets for this “tattery are constructca to allow a maxinum cepression of 5 Cevrees t. pemiut firine at tarcets on the inner e're of deep water arcas. The stops should therefore always be kcpt in tre upper set of holes. The parapets for this >atter; are constructed to allow firing not lower than horizontal since that is low enou:n to cover all important ceep water at short ranzes. ‘the stops must never te left in the upver set of holes since if this were done and the fun were tripnred while set in cepression the muzzle would strike tre concrete parapet and seriously Gamare the carriace, A spring buffer is attached to each chassis near the bottom of the elevatic:, rack csuices to prevent any shock,if ty chance the racks run Cova of their ovwm weicht,and also to serve as an elastic stop for elevation, VX a 47.Q..hnat is the purpose of the helical (criled) spring; at the rear of the elevating worm? A,the part of the worm shaft on which the worm is mounted is square. iUxcept for tne helical sprins nothing prevents the worm from slipping to the rear on the worm shaft vhen it is turned. the spring holds the worm forward in place. If any force rreater tnan the resistance of the spriins turns the pinion shart tne worm will move to the raar on the worm shaft compressing the spring. «icn tne force is removed the sprine vill expanc anc force the worm forward in place. In this way te spring protects the clevatin: mechanism from any dangerous strains due to a strong downward force exerted on the elevating rack durin= recoil. 48.Q.Describe the sisht standard and platform? Astne sight standarc is mace i:. one piece anc is bolted to the racer. The sighting cear and traversin>s and elevating maneuver gears are atiachse¢ to it. The platform is supported in front by the standard and in rear by the platform ladder. 49.Q.ihhat is the purpose of the trunnion sight bracket? A.It is intended primarily for emercency firings after the sight stancard has become unserviceable. It also affords an excellent place for testince the sight as outlined under VIII Pointing,\c) Emergency Systen, page 4.7 . - x -- mechanism? we 51.Q.shat is the purpose of the siv't bracket and sightin Aesne sight bracket secures the sicnt in its proper position. she sightin;, mechanism conuectins the bracket with the front enc of tne elevatins worm shaft causes the sicht to be elevatec or denressed with the cun. 62. %-Is this used now? what case do you fire in when you use it, ANo, Case re 53.Q.Describe the traversing ccart A.Tie traversine ceur is oreraice by turning the traversing crank. The connections from the crank to the traversing rack consist of the Sraversins crank shaft,a vertical shaft insice the traversing gear standard,and another vertical shaft supported in the racer,and the bevel gears and pinions connecting these shafis.Q@n the lower end of the vertical shaft su,ported in the racer is a pinion whose teeth mesh with the teeth of the traversing rack. The rack,beins fastened to the base ring,is stationary,so that when the pinion rotates it travels around on the rack forcing the carraige to move with it. The traversins maneuver hand wheel anc the sears connecting it with vertical shaft inside the sear standard on tne racer, permit the gun pointer to traverse the carriage. she maneuver gears are engaged and disengaged by a clutch attached to the gear standard. One revolution of the traversin;; crank turns the gun and carriage thru 4.09 degrees of azimuth. whe traversing maneuver hand wheel makes 6 1/15 turns for every turn of the traversing crank hence one revolution turns the carriage thru 0.60 degrees of azimth only. The traversing crank is intended for the use of a man on the gun platform who can traverse the carriape rapidly to the approximate azinuth,especially when changing target. she C,A.D.K.-1909 provide no traversing detail for the 6 inch disappearing carriage but autnorizes the battery commander to make such modifications of the Service of the Piece as he deems necessary. The traversing maneuver hand wheel affords the gun pointer a slow motion means of traversing, the carriage under his ow control. 54.Q.Describe the action of all. the parts of the retracting mechanism. A.The retracting handle on the right side of the carriage operates through 2 small and 2 large spur gears the retracting shaft supported in the lower rear part of the chassis. On the shaft are two drums for winding in the two wire retracting ropes, The ropes pass from the drums under and over the retracting rope sheaves on the upper rear ends of the chassis rails to the hooks provided on the upper ends of the gun levers over which the eye socket on the end of each rope is hooked. Two cannoneers can easily retract the gun to the loading position by operating the handle. The retraction ratchet-wheel pawl and retraction ratchet are mounted on the retraction pinion shaft outside the right chassis and serve as a safety device to prevent the handle from spinning if it escapes from the contrul of the cannoneers,. Until the pawls enrage in at least the first notch of the crosshead rack the loss of control of the retraction crank would allow the cun to return to the "in battery" position 55 eQeimat precautions must betaken durine retraction? a.l.see that the ratchet is encaced. 2.Guide the ropes on to the drums without kinks or slack,3.S5ee that the ropes wind on smoothly without lapping ove themselves or the rid«es between the rrooves of the drum. 4.5ee that the ropes are under equal tension,so that each will co its share of the work. acjustment should ve made at the rope clamps on the drums to socure equal tension. 96.Q.hat is the purpose of the safety lanyard attachment and how is it accomp- lished? Aso prevent firine the picce by a pull on the lanyard until the piece is in battery. sane branch of the lanjard from the primer to the ring can- not be pulled taut unless the cord in the housing mounted on the rear of face of the elevatinz band of te “un on the right side will unwind and come to the rear. This core will nov wavine until She pawl which holds the reel on which it is wound is relveused Ly tse Cam on the cne of the vlevactin, arm. The cam shoulc nov release the pawl until tre top car siase is within the distarce -qual to the caliter off the gun from "in batter, position, tnerefo.e <. picce caniovw vefired by lanyard until the muzzle is well aivove the parapot. For effi. of firin, tre cun pefore it is full; in battery,see V Service of tne Piece,Duties of No.9,parzc 57.2.How do the clectrical wires reach the carriuce? A.They pass thru a cable in a duct in the concrete to the counter weight well. In the well they center a terminal box.From this they pass thru a flexible metallic conduit to tne vertical pipe conduit at the center of rotation of the carriace. The flexible conduit in the form of a loop is necessary to allow the carriace to be traversed without breakins the wires. ‘lhe different wires pass from the vertical pipe conduit to their respective lamps. 58.Q.How many lamps are on the carriace and for what is each used! A.4 16-candle power lamps and 3 8-candle power 3 of tie lé-candle power lamps are for the general illumination of the carriace. These lamns are controlled by one switch located under the sightins pl«tfom:. the fourth is a portable lamp. One 8 candle power lamp is used to illuminate the elevation pointer,i for the azim) inches. 83.Q.The penetratins power of the projectile fired from this gun places the «m in which class of armament and for what use? A.($ee par.8 C.A.D.R.1909) In the intermediate class of armament which is used primarily to attack unarmored vessels,but which may be used effectively to supplement the primary armament in the attack of armored vessels,or the secondary armament in the defense of the mine fields. 84.Q.What data is marked upon the muzzle? A.the number of the rifle,placs and data of manufacture,weight,initials of the inspector and the model of the piece. 8>.Q.Is any cause for alarm if after firing the first few rounds the tube is found to project 0.02 or 0.03 of an inch beyond the chase hoop on the muzzle face? A.No. It is not uncommon for this to occur after the first few rounds. the hoop and tube are faced off at the mizzle before the gun has been fired. Firing a few rounds relieves some of the internal strains due to shrink- age allowing thetube to project at the face. she parts are locked together intermally. If there is no marked increase in this projection from firings after the first few rounds it is no cause for alarm. BREECH MECHANISM. 1.Q.What is the name of the breech mechanism and firing attachment on the 6 inch R.F.gun model 1897 MI ? A.Stockett Breech Mechanism fitted with the combination electric-friction firing attachment. 2.Q.What are the principal parts of the brevch mechanism? A.Breechblock,gear segment,block carrier,lever,pinion,latch,and obturator. 3.Q.Name and describe the different parts of the breech block,and give the purpose of each part? A.l.Threaded and slotted sectors. ishese sectors are formed by cutting a V shaved screw thread around the outer sufface,’ then *ividing the circum- ference into eight equal parts,and cutting away the threads of alternate parts, ‘the parts from which the thread is cut are the slotted sectors. The threaded sectors on the block mesh with the threaded sectors in the breech recess when the block is closed and rotated, thereby preventing the block from being blown to the rear when the gun is fired. ‘the slotted sectors in the breech recess receive the threaded sectors of the block,and the slotted sectors of the block fit over the threaded sectors of the breech recess wnen the block is closed prior to rotation. 2.Guide cylinder. ‘this is the rear part of the block,smaller in diameter than the block. It fits in the cylindrical hole in the block carrier. It supports the block in the block carrier and guides the block in its motions of translation and rotation. The gear segm-nt is attached to its rear face. It contains the locking recess into which the latch bolt fits. 3.cuide groove. ‘this is the groove in the rear end of the block around the guide cylinder. The guide flange on the block carrier fits into it and assists in supporting and guiding the block, *.Stop flange. It is that portion of the rear face of the block which is outside the guide groove. When the block is drawn toward the rear by the by the rack on the gear segment and the pinion on the operating lever, the stop flange strikes the bottom of the stop groove in the block carrier and prevents the block from being translated farther to the rear. 5.Axial hole thru the block. shis hole is for the spindle and the spindle ball washer. . 6.Locking recess, It is cut in the guide cylinder,When theblock is translated rearward,the latch lever and spring force the inner end of the latch bolt into the locking recess. Thus the latch bolt locks the block to the block carrier. 7.Four oil holes are drilled radially from the exterior of the block to the bottom of the guide groove to facilitate oiling the bearing surfaces. 4.Q.Why is the front part of the block reduced in diameter for a short distance back? A.ihis reduced part of the block leaves a space in the breech recess of the gun in which fowling may collect without interrupting the working of the block, >.Q.Describe and give the purpose and action of the gear segment and pinion? A.the gear segment is fastened to the rear end of the guide cylinder by a spline (two strips on the rear face of the guide cylinder which f it into two slots in the gear segment) and two screws. On it is formed a segment of a bevel gear and one tooth of a rack. On the pinion,which is secured to the operating lever,is a segment of a bevel gear and two teeth of a pinion. ‘the bevel gears cause the breech block to rotate, and the short rack and pinion part translates the block (moves it along the axis of the gun). When the breech is opened the action is as follows: one continuous motion of the operating lever rotates, translates, and swings the block¢ clear of the breech. During the first part of the motion the bevel gear on the pinion meshing with the bevel gear on the gear segment,rotates the gear segment and breech block 4° in a counter clock wise direction around the axis of the gun thereby disengaging the threaded sectors on the breech blook from those in the breech rec-ss. When the rotation is completec,the rack tooth on the gear segment comes into place between the two pinion teeth,and furkher rotation of the pinion by the operating lever translates the block back against the block carrier withdrawing the obturator from the gas check seat. she remainder of the movement of the operating lever serves to withdraw the block from the breech by swinging it to the right around the hinge pin as an axis. In closing the breech the action of the different parts is the reverse of the above. 6.Q.How is the block carrier supported? A.By the hinge. A hinge pin secures the block carrier to the hinge lug on the rearmost hoop. 7eQeName the different parts of the block carrier? A.Stop groove,guide flange,cylindrical boring for guide cylinder,pinion seat, recess for latch,recess for spindle key. 8.Q:How is the pinion and operating lever secured to the block carrier? Avthe pinion pivot passes down thru the pinion and lever and screws into the lug which forms the pinion seat. the pivot is prevented from unscrewing by the pivot nut secured to the pivot by a thru pin underneath the lug. 9.Q.Where is the latch mounted,of what does it consist,and what is its object? A.the latch is mounted in the block carrier. It consists of the latch bolt, latch lever,latch spring and latch lever pivot and the latch bolt seat and tripping stud secured to the face of the breech by screws. When the breech is closed the latch locks the carrier to the face off the breech, and when the breech is opened it locks the breech block to the block carrier, y ~ O wee Sr ae 8 VY. , : awh towy- nn” 2° ‘ 7. “hye. 2/ 10.Q.Descrgbe the complete action of the latchi "A.The complete action of the latch is as folhows: With the breech closed, the outer end of the latch bolt gests in the latch bolt seat,locking the block carrier to the breech off the gun; the inner end of the latch bolt bears against the guide cylinder of the block,and,at the end of the motion of rotation of the block in openinz the breech,rests in line with the end of the latch groove. When the block is withdrawm against the carrier,the bolt rides down the inclined bottom of the latch groove and its outer end is withdrawn from the latch bolt seat,freeing the block cxrrier from the breech of the gun. At the end of the motion of withdrawal the inner end of the latch bolt enters the locking recess in the breech block. As the block carrier is swing away from the gun the end of the latch lever clears the tripping stud so that the fuli force of the latch spring comes into play and the latch bolt is forced ' to the bottom of the locking recess,securely locking the block to the carrier. In closing the breech the action of the latch is the reverse of that just given. With breech open the block is locked to the carrier. As the latter is swing against the breech face of the gun the tripping stud,by means of the lever,raises the latch bolt far enough from the bottom of the latch groove locking recess for the end of the béalt to ride on the inclined bottom of the groove as the block is moved forward thru the block carrier. As the bolt rides up the inclined bottom of the latch groove its outer end enters the latch bolt seat and locks the block carrier to the breech face of the gun. 11.Q.0f what does the obturator consist! A.Mushroom head,spindle,gas check pad,front and rear exterior split rings, interior split ring,filling in disc,spindle nut,spindle ball washer. 12.Q.What is the object of the obturator? A.to prevent the escapes of gas from the powder chamber to tho rear during firing. 13.Q.Describe the spindle and mushroom head? A.the front end of the spindle is enlarged into a mushroom shaped head which plays the part of a piston head at the rear end of the powder chamber under the action of the powder pressure. she stem of the spindle passes thru the axial hole in the breech block,the rear end being threaded for the spindle nut. The axis of the vent is the axis of the spindle. the rear end of the vent is enlarged to form the primer seat. In the mshroom head is a copper bushing around the vent to protect it from erosion and to enable repairs to be easily made, The spindle nut screwson the rear end of the spindle and secures in pbace the spindle,gas check pad,split rings,and filling in disc. 14.Q.What is the object of the ball bearing washer? A:It is interposed between the spindle nut and the breech block to reduce the friction between them when the block is rotated, 15.Q.Describe the gas check pad,split rings,and their action? A.The split rings are made of steel and are split diagonally thru at one Place to permit them to be expanded and contracted. The exterior ones are made of slightly greater diameter thanthe gas check seat so that when forced to place by closing the block the resulting compression will press them hard against the gas check seat at every point of the circumference. In order that the interior one might fit tightly around the spindle its diameter is slightly smaller than that of the spindle at its seat. A slight shoulder on the rear face of ‘he mushroom head and the front face of the filling in disc supyort and center the extcrior rings. ithe gas check pads were formerly made of asbestos and tallow but are now made of 3 parts asbestos and 1 part nonfluid oil. the later ones are marked N.¥.0O.to distinguish then. Aabestos is used to resist combustion under the high temperature of the exploding power. A fluid oil would run out of the pad and leave it dry so that it whuld no lonzer be plastic, It is compresscd under heavy pressure and covered with canvas. Under the high pressure of the powder gas on the mushroom head it moves to the rear compressing the yielding pad which expands outward and inward. The pad in expanding; outward by virtue of the shape of its shoulder under the exterior split rings,forces them tight agains} the gas check seat,and,in expanding inward,it compresses the interior ring tight around the spindle, the gas from the chamber cannot escape to the rear between the gas check seat and the exterior split rings,nor betveen the spindb and the interior split ring. ‘ihe gas check is then metal agains} metal and not canvas against metal. the movement of the musnroom head to the rear under the pressure of the powder gases may at first seem to produce a tendency toward cushioning effect similiar to that exerted by the counter recoil buffers when . the carriage goes into battery. It is essentially different however in these important respects: (a) No provision is made for the escape of any of the imprisionec mass of the gas check pad. \b) The maximum pressure is not encountered at the beginning of t the compression of the pad hence the full movement is undoubtedly taken up before,or by the time,maximum power pressure occurs,otherwise the system would fail as an obturator (gas check),and the maximim pressure is exerted on a solid mass ana therefore transmitted in full intensity to the breech recess threads, . (c) the movement of the mishroom head is too slight to be important. (d) The material of the gas check pad is too nearly of the nature of a solid. 16.Q.What is the object of the filling in disc? A.It acts as a steel washer between the pad ana the front face of the breech block. The projection on its front face assists in centering and supporting the rear. split ring. A 17.Q.Describe the purpose of the spindle key? A.The spindle key extends downward thru the block carrier and the block. Its lower end fits in a slot in the spindle stem,and prevents the spindle from rotating. she spindle mst not rotate because the firing mechanism attached to its rear end mst be kept in an upright position. The key allows the block to rotate the proper amount by means of a slot in the guide cylinder in which the key fits. WIRING ATYACHMEN, 18.Q.Name the principal parts of the firing attachment! A,Slide,slide housing,ejector,firins leaf,contact clip,firing cable,circuit breaker,and safety bar. 19.Q.\here and how is the housing attached? A.To the rear end of the spindle by means of an interrupted screw thread. spline screw secures it in place. 20.Q."here ana how is the slide attached? A.The slide is securedin the housing and has a vertical motion in guides wnich project from the rear portion of the housing. 21.Q.‘7nat is the action of the slide stop? A.The slide stop has a horizontal movement against a spring in a hole in the housing. The inner end projects into a groove in the side of the slide and limits the vertical motion of thie slide. The spring pressure keeps it in the groove of the slide. 22.Q.vescribe the position of the firing leaf and the action of the firing leaf and slide when a primer jis fired. A.The firing leaf is pivoted at its upper end to the slide against which it lies flat except when pulled outward. A notch is cut through both the slide and the firing leaf so that,when in its lowered position,the slide supports the head of the primer against the pressure of the power gases while the primer stem is allowed to project through both pieces, leaving a clearance between the firing leaf and the button of the primer of about 0.06 inch. When the firing leaf is pulled to the rear its rear face, pressing against the button, draws the stem to the rear, exploding the primer and firing the gun. 23.Q.vescribe the position and purpose of the contact clip. A.The contact clip is held in a housing which is secured to the firing leaf by the housing nut: and is insulated from the leaf by the housing insul- ation, The contact clip fits around the button _- on the primer sten, connecting electrically the contact clip housing and the primer sten, two parts of the firing circuit. 4) ¢ 84.Q.What parts of the @irine circuit does the firing cable conrect? A.Cireuit breaker contact piece with the cpip housing . 25.Q.Describe the circuit breaker,its purpose and action? A.It consists of two parts,namely,the circuit breaker contact piece secured to the gear segment and insulated from it,and the circuit breaker housing secured to the block carrier ana insulated from it, and containing the circuit breaker contact pin. The purpose of the. circuit breaker is to prevent the firing cirauit from being closed until the breech block is closed ana completely rotated. When the block is rotated in closing the breech the contact piece comes in contact with the contact pin. The end of one of the firin= cables is secured to the circuit breaker housing by a fork. 20.Q.vescribe the ejector and its action? A The ejector consists of a horizontal and a vertical branch with a pair of trunnions near the angle. It is supported ir the housinec by these trunnions,and in its normal position the lower branch,vhich is in the form of a fork,hangs vertically over the mouth of the pri:er seat, enracin>; the rim of the primer on two sides. she horizontal branch projects to the rear into a recess cut in the front face of the slice, ahe lower end of this recess is a cam surface. “hen the slide is raised,tnis can surface forces tne horizontal branch upvara,eject:: the priner. when the slide is lowered,the ejector drops into josi ther agalnsy the mouth of the prinsr seat. 27 .eQ.Descrite the safcvty bar and its action? A.the safety bar is a lever pivoted in the slide housing and actuated by a stud on the cear secment workins in a slot cut t*rm the outer end of tie safety bar. At the beginning of rotation of the block in openins the breech the inner end of the safety bar rotates inward,enterin; a slot in the rirnt side of the firinc leaf,thus preventin: any movement of the firin: leaf,and therefore an accidental discharre of the gun,except when the wreech is fully closed. 28.Q.Describe the process of dismounting and mou:ting the firing attachment and breech mechanism? AOpen the brecch. Unscrey safety bar pivot and remove safety bar. Detach firins ca:le from circuit breaker contact piece. to remove slidc,mll outward on slide top and lift slide. from housing. Un-serew housing spline screw and revolve houging 90° to the richt,when the housin® may be drawn to the reer from the spindle. Unscrew the spindle nut and the spindle key screw,and remove the spindle key. Be careful not to remove spindle nut and spindle key before opening the breech,as in that case the split rings are liable to drop dow and prevent the withdrawl of the block. ‘the spindle,split rings,pad,etc.,are then free to be removea from the block. take out the two gesr segment screws and drive off the gear segment,using a copper drift to prevent injury to the metal. sake out the latch lever pivot and remove the latch lever,spring,and bolt. fhe block is then free to be removed from the carrier. Drive out the pivot pin and remove the pivot nut,unscrew the pivot, and the pinion and lever are then free to be removed fromthe carrier. Drive out the hinge pin,being careful to support the carrier while doin, so,anc the carrier is then free from the gun. The process of mounting the mechanism is the reverse of that of dismounting it. TT GUNS Av'D CARRASES. (b) Packing stuffing boxes and cleanings recoil cylinders. 1.Q.20w is the old packing removei from the stuffing box? A.First dra: all the oil from the cylinders,then with spanner 2.Q.How A.Put wrench. remove the follower and the gland. Kemove the old rings of the packing,using the extractor. Fxamine the old packing and throw away that which is not fit for use. If any of the old packing is to be used,it should be put in after the new packing. [If it is difficult to remove the old pnacking,use the packing extractor as follows: Force the extractor down on the nacking and turn in a counter clockwise direction until the hooks have engaged in tne vacking and are turning it. Then continue to turn ina counter clockwise direction and rull the extractor cut gently at phe same time. The wracking will conform to the threads cf the stuffing box and may be brought cut easily and oo tkout injury to threads cor vacking.(C.A.D.R.19C%.7ar. 87C and Ordnance panrhlet No.1438.) is a stuffing box renackea? on the riston roa one ring of Carlcck's “atervroof Fyaraulic packing and force it well to the bottom of the stuffing box with a wooden stick or mallet. Treat each layer the sane until six rings of new vcacking have ceen inserted,or ar evel amount cf ola and new racking,if any of the latter haa use r used. Place the alves of the cland on the followez, being careful that the halves of the gland de not bind on the screw threacs. No more force should Se used on the syvanner wrercn han that cof two wen;generally that cf one Lan if Bulricient. LL o + +h YA, a+ The addition oF a pipe to M55 eg end of the gpanner wrench ef e ete roe , L . 3.9.Fow can you tell if the stuffing box is cronerly tighter A.There should oe about one inch cetween the flange or tne follower 4.9.™hat should be done to keer A.,Tthe 5.Q.¥or and the rart irto which it is screwed, box nroverly tightened follower shoulda ve tich gehtened from time to tine. If the follower is screwed int h i e stuffing Dex too tightly an urn- necessary amount of friction will he “produced on the sistwon rod. If when tre follower is screwed in the *flarve strikes the bex,another ring of nacking 6 should be added. (ordnance pan: nlet ™o.1588). what ars drin vans used? A.To catch the suwall amount of o1i1 that is likely to soak throug: and drip from tne stuffing boxes when the carriage is not in use. af 2 6.9.How often should recoil cy'’iiders be ewctied ond tow often cleaned: A.They should oe enrtice at least once every three montrs ana clean2a once every Six montis (Ordnarce r namrhlet 1¢68). “hey should be cleaned a short time srior to each firing (CLA 869), 7.Q.Describe in detail the methed cf cleaning recoil cylanvers or A.la (b } Gisayrearing carriage using a plumber's hand force rump with hout ten feet cf suctton hese and fifteen feet cf aischarce tube? Trip the gun. Remove the oil from tne hydraulic syetein as follows: Obtain a length of hose sufficiently long to reach from fror the é emotying courvling to the cun platform,make one end fast to the equalia ing rire univer the em-»tying ccuvnling,and rlace a funnel in the end 80 that when the coupling is onened oil] will flow into the funnel and barough the hose. Proviae a reserve tank for hydrolene oil and place it on the cun platform nea the chassis. Pass the end of the: hos through the orening in vhe chassis just ir front of tne traversing shaft ,place a sieve avove the opening in the tov of the reserve tank and hold the end of the hose just atove the sieve. 'nscrew the cre ing couvling and the oil will flow from the cylinders (roth filling plugs having been taken out) into the reserve tank. This avoids snilling cil on the carriaze and the platform anc ts 4 saves the labor of mandling it in buckets. (c)Retact the eun until the «istons cre in the middle of the cylinders,then slack away until the vawls engage “rn the ratchet teeth on the crosshead; observe that the pawls are engaged croverly in the ratcnet teeth,and tnat the pistons are not unaer the filling holes. (ad)Remove the piston rod brackets from the rear ends of the chassis rails. Take off the two nuts on the front end of each piston rod,remove t*e rear cylinder head frou each cylinder, and rull the rods carefully to the rear out of the cylinders. Before removing any part it should be marked so as to insure its beings assembled in its correct position. (e)Clean thoroughly each cylinedr fron both ends with kerosene oil forced in with a und numn,then wire dry with clean cotton waste and clean the cistcn reds. The equalizing and connecting pipes should be disnounted and cleaned by forcing kerosene cil into then with the pumn. (f)Assenble the equalizing and connecting rines,leaving th throtfling valve wide open. Tnsert each niston rod in its cyasainder,exercising care to nrevent birding of the pistcn, burring of the walls, or cther damage. Assemble the two nuts on the front of the rod; move each rear cylinder head foward into its seat in the oylinder. Assemole th: niston-rod ovrackets to the chassis,and then secure firmly the rear cylin~ der heads to the cylindars ard fill tne recoil cylincere vith hydrolene oil. This will require some time,as the oil can enter the warts cf the cylinders in the rear of the pistons only through tne equalizing prires and the throttling car orifices. Insert the filline cligs wien avrarerntly fillec, clese the throttling valve,and retract the gun te the load- ing ~osition. Comnlete the filling of the cylincerrm anc close the throttling valve to its nroner setting. “Yor this methcda a plumber's forcerunn ia surnlied to each coast artillery cost, alac suction-hose discharzse tube. Insrect carefully all rar*’s disrounted and note that they have been azsenctled nrorerly. Then the viston-rod nuts shoulda be loosened to insure the rca being located centrally in the cylinger and the nuts tigntera, The gun snculd be retracteu and trixvvoed several times to insure that all rarts are in nrower working order. (C.A.D.i. 1609 ,Par,859). 8.Q.Describve the method of cleaning recoil cylinders on disarrearin; carriace wren nlunvers hand rumy,hese and tube are rot used? >) ose the erotving counling and »ut ten gallons of szercserne cil plugs. With the use of re- traction cables bring the pun fror battery and allow it to go in battery slowly with the ca>vles:‘on,controlling the motion by the retraction cranks. heseat this cneration several times. In this way the kerosene will be forced through every portion of the recoil cylinders and vives ard will clean all parts. Vith the gun in battery the eurtying ooupling is unscrewed and the kerosene allowed to drain out. After kerosene has drained cut place about @O gallons cf hvdrolene in the cvlincers and work the gun in and from battery with cables on,in the sane nanrer as before. Drain this hLydrolene out ard throw it away cr save it to flush cut vintle “carings. A*ter cylinders have «rained refill with hydrolene. When batteries are equinred with electric nnver for retracting, the foreroing aeathod is an easy one. Cuns are drawn from cattery by rower and allowed to go »%ack witn four men on the retractirg cranks (for 18-inch guns). If retracting is to ve done by hand,labor will be saved by removing all hand counter- weights before starting. (d)If cylinders have not been cleaned for so long that feuale rortions of countor-recoil buffers have vecome nacked with hardened oil sediment,the gun will either co in battery by creecing the last inch or wavy not go entirely in. If the above methoa does not serve to remove the costruction,the cylincer head must be taken out and the buffers cleaned by hand. (e)In employing this method a careful examination should ve nade to see that the cables are in good condition,and the cun must he allowed to go into batterv slowly and evenly. (C.A.D.R.1°C9 r ~ Par,5°09). Vil lige 5b it niighlaced 36 CUN CONV ATDER Fire-control svsater. (a) Ceneral knowledge of For this sudject,see the and C7" POINTER, that in use at tne batterv, same subject under Plotter II(A). I] 1.Q. A. 3.9 2On CUM GO ANDRA 2 CIN DOINOEE, /. a é€@. ww ple YY yu Cun arc o (c) ATIVSTYENMe, Can the sight stancd ie amnearing carriacse® nodel . — 5 ‘ o . - =“ yu ‘ cc o - 3 2 3 o 16t< for S-ineh gun ve adjusteu eo that T.e Line of sight ard axis o*7 the ‘ore can ‘Se Converged umon a cesired neint rm : - % - . 4 c ~ Y ‘ + V, VL. a iad = + Wo. The sicht stanuaru ana tie axis of the sore ara the line % ag justec to rnarallelis..,canret Oe ° ~ \. 5 ee 2 . I. of sight, ,teaving once bee > ~ aa + £ -,*° at CNS. : 1 *. “ ~ “n 4 easilv La Ca My c aia US yviL Cy C ° TLE, sla mb COG UB +7, ert - no 7 ee e7 . es r a He oe _—~ ob \- —_7% = ~& rroperl; naG@ GAPrling CA® sicr Tesy,treve int no way C1 ey t A 2 we ” - (ca QO - ~ ta , rye e correotin-: it. (Sea Bere Firstineg Pa.e 4 . ww wo 22 oO nt is nada on tne sicht standard oF this tarria 3 it ada? oOo ¢ cB ct ie —$ wv llel mechanism nay he acjusted T with tne aictht on the sicht t be rlaced in rarallelian with t ring 4 Q re >) wt a wh ree) 3 }-- Cros ct 4 - uy oD "me ion. To de a quadrant OL mat siticn. Put ¢t e courling t with elevating worm a using a wrench on the si the signt standard,until that the sight is in a hori the co surline. The line of sigst anu axis of the bo carallel wen the sight is set for zero elevation ction and the telesanve lonvitudinal level is cen aa aN ' 4a Lo 798 th a Nn + uy b “y rart projects nz to the 3 tyr -O oO. th on nch oan what sdaustnent is nade to Sring the line of s ullel @ 6 4n7e axis of the wocore? % atts >) ct x’ oO a) Oo 0D Ay Q cf wo Fe oS ‘3 Dice SG ct CD Models of 1° °5 and 1605 M.T.,a 12 arm oOracsxet 18 engugeda cy t geht atandard. "Vy means sicht ary racket, 32205 azimuth and the line of s the bore. To rake thea object fabout GCCOCO ya bore sizgtt,set the then vring the lin pet screws. “Our % Stanuard turo.u. Signt arm Tracxnat. larre r than tre The acrews shoul ct 29 I oe 4) oo 2O a % 2 oO »? rt re) i ic Q a . > is wie +t i409 few ly to oun at a cable) dy means of the sight at Zero, cat bv neans cf th into the Bint t tne vase ct the © ci: in cianeter lts,whic nt adiustment. Ne loosened, tn@ adjugtiuert mauve then th ni the ad; ‘attuant verified. (See O.P 17C y i ge ob ema - D wy a ao to.8 5 ra: r: wD iO A ct a eo r ha Suinn* Ataannanrineg sarvioza wnat of WOT bam a sinilar agisannearing carrizcses nodels of 1EC3,1SC5 and 1°C5 M I dort e e On ~ ON eo aaiustnent. In fact rractically all aisa>vearing carria_es have verovisions For this adjustrant,aiffering from the aocve in wmwechanical cetails only. Throttling valves. 4.Q."ow are vroner settinz: of threttlines valves aaterninea? A.The setting of the valves oest suited to era conaitions of loading,full or rractice charves can be determined only ov exceriense in aotual rirings on e@ac oh rartio alar carring@. Ditterer.. Carriages may require different Pee GS 28h [Le same Carriazesmay at ai**erent times require different gsettinzs Tor tre@ sane conditions of loadins if it is ina naterally Gif?- 2 P- * . e arert aonarition as to olecHées and lubrication of marta. ford.Panchlet No.1Aas). 5.9.What recoracs should ettings? A.It is necessary that careful records be kent of the setting of the valve,the conditions of lovwding and recoil,vhe elevation of the niece ang anv Abnormal eenaition cf the carriage whier night effect the Freedor of tts Operas ion, These records ehould be studied in the light of all these circunstances to obtain rerfect working. (ona Manchlat No.ee), 6.9.tn lack of eaxnerianse how mach shoulda the valve he orened for full chars ag? A.To about C.C5 Sq.inch but not more (Ord. Pamrhlat %0.1586). rer . .. aa ~ . ~ +, 2 o fw ~ r . © 7.Q."hat is tre rurrcsae of the nadlock for locking the valve yoae' valve 327 A.To cuardad against acciuantal or unauthorized changes in toe Stine. The valve should habitually be kent locked wut this should OX Se not c@ ungarst7ca 4283 disecuratins amination Le - — we and handling o Fo tne valve, a3 it is highly vesireadle that the. nearacnrel unuerstand the construction ane oreration of the fay valve, (Ord.Panrhlet Yo.168°). “as Check Pad. €.Q."eecribve the method cf adjusting the -as check vad on *he f#incn SOT 4 T.? gan,nedel 16 i A.Close tre creech with the s~indle nut lcose,bit not loose encuch to rernit slirning of the rad or sclit rings,rotate the clock one-half. With the mechaniam in this vcositicon screw ur 1 the srindle nut a8 tient as it can be screwed with the wrenches provided. It 13 necessary to insert the end 97 a screw-driver in the ovenins of the nut in order to arread if suffictently tc a@llow its rotation without rotatin« the srindle. Clann tie emirndle nut and rotate the oreechslock until the breech is Closed connletely. This last oreration nresrses the vad irte its seat,cue to the forward motion 9° the block. Then the nad sniould be in ornoer adjustment for firing; this nay be tested Dy turning the nushroom head by hand. It should turn easily, but without clav. () Q. co cO S Bz The breech mechanisan of the G-incoh guns, models WS7 MIT, 1©C3 and 16C5 have a sclndle key which rrevernts the sxindle and nushroow head from turning. The carts of the abdove me*:ou involving the turnin: of the nushroom head does not arrlv to these sins. (G.A.0.5.Par.873). ELEVATING CEKAR. “What adjustment is rade on the elevation sear 9* tle G-inch disarrearing carriaze motel 13957 The elevation eointer mast be adjusted to indicate correct elevation. 1C.Q.How ie the acjustwent wade? A.Using a clinons ter,bring the gun successively to the elevations QO degree 5 dezrees and 10 decrees, Adjust the rointer sc tna. it will coccineide with the corresnonding csexree marks or. v3 range drum. Atter this has once been cone 19C9 requires that it be dowelled in nlxce -—- = - ee ee ——-- - 11.Q.How is the resistance cf the elevating worm anrring teated? A.With the gun at zero Gegrees elevation,a weight cf not to excead 50°09 1548 i3 arvlied on the elevating arm G.O.3 1218 and Cir.13,".D.-10. This requires considerable ingenuity on the part of sun cenmnanders and battery connanders, especia lly in a G-inch vattery,to obtain the maxinium “test prescrived, [t is net material to the results of the test Whether the gun be in ‘“attery cr not. The in-battery vosition affords much more room in which to work, The conditions which do affect the severity of the test are tne roint of arplicaticy tion of the maximum weicht and its line of direction relative + to fhe notion cf lower end of elevating arn along racks. "ne i+ most severe conditions are preduced by “arnlying the Welght at the rack erd of the arm in a airenstion marallel to the notion of the racks. The netnod of securing the maximum weipht cf sull ynrescrived devenis uncon the means available. [t is usuallv accomrlished oy GREASE GTyPs, Note: "here ar@# no 7Yre@a3e 2un3 nrovided for 6-inch disanneariny. ww 4 4 7 ae i 12.9 .Ucw should carriages ,nodel of 1698,5ut all of the later S-inch disarres- ring carriages are crovided Wwitn them. crease cuvts filled and adiusted? £.¥ill them with lubricant 44 to the bottom cf the bevel at the ter of the cup being very careful that no grit or aiirt gets intorthem. Put on tne can,takires care that the leather racke: Follower enters *he cun rrovnerly and is not caught nor cert. Screw the can down until the savring rod projects about 4} inches aoove the head of the oar. © igh Bb ax Allon 92 833 37 VIII POINLING. (a) Methods of pointing and pointing tests. 1.Q.Name the three methods of pointing? A.Case I,Case II,Case III. 2.Q.Describe the method of Case I? A.This method of pointing is used only with rapid-fire guns where means for laying in elevation by quadrant have not been provided. Direction and elevation are given by the sight. The gun pointer adjusts the sight in its seat and sets the elevation and deflection scales for the indicated range and deflection,respectively. He keeps the line of sight as nearly as possible on the designated point of the target and the piece is fired as soon after the command READY as it is aimed accurately. In firing a series of shots he observes the splashes if possible and, when necessary,c..an,es the setting of his signt to correct for the deflections. He changes the elevation to correspond to the chansing range of the target or on orders from the battery commander. With two gun pointers,one controls the elevation and the other the direction. (€.A.D.R.531 1909) 3.Q.Describe the method of Case II? A.this is the normal method of pointing all guns except those of 6 inch or smaller caliber on barbette mounts. Direction is given by the sight and elevation by the range scale attached to the carriage. the range setter lays the gun for elevation in the manner described in the Duties of the Range Setter under the "Service of the Piece", page « the gun pointer sets his sight,causes the piece to be fired,and corrects for error in deflection as described in Duties of Gun Pointer under "Service of the Piece", page o(C.AeD.R.032 1909) 4.Q.What is Case III and when is it used for guns? A.Direction is given by the azimmth circle and elevation by the elevation scale or by quadrant. the use of this method for guns is limited to batteries where fogs or other local conditions make it necessary in the opinion of the Coast Defense Commander to prepsre to fire at a target obscured from the guns.(C.A.D.R.533 1909) 5.Q.State the advantage in firing by Case II rather than by Case I? A.1.The gun pointer,having to lay the gun for direction only,can watch his target more closely,set his deflection and lay his gun in azimth more carefully. He has a better opportunity for spotting hds splash and is less apt to make his corrections in the wrong direction. 2.the range setter,by observing his time range relation can keep his gun laid in elevation at all times. 3.Practically all range setting and elevating mechanism is under cover. 4.With Case I accuracy of fire is dependent upon the gun pointers accuracy of bisection of the desired point of impact with both the horizontal and vertical wire,while in Case II accuracy of fire is dependent upon his bisection with the vertical wire only. a i) .. 4 rL IB 11.Q.Are there any advantaces in firin: by Case I instead of Case II with the signt on the trunnion bracket! A.Firing by Case I instead of Case I. climinates errors due to: 1.Base ring being out of level 2.Range pointer not properly adjusted 3.Errors in range graduations 4.Back lash in elevatinz mechanism. this includes the "stickinz" of the elevatin: racks with the resultin; chanse in elevation of the cun by jumps wnile elevatins. This is some times found in carriares over certain parts of the path of the elevating racks. Yhis difficulty should be remedied by the ordnance macninist,when found. 12.Q.\iiich Case should be employed when practicable? Wh;? A.Case II. Because all of the disadvantazes and errors under Case II have “ minimized or eliminated by methods and apparatus now in use. While only the first two objections to Case I are capable of being eliminated by design of parts or expert workmanship. he last two objections are inherent in Case I. 13.Q.In how many ways may Case II be employed with the sight on the trunnion bracket? A.In one way only. Direction is given by the sight and elevation by the range scale. 14.Q.If the range disc becomes unservicable which method of firing Case I should be employed? Why? A.The second method where sight elevation instead of quadraht elevation is set on the sight,becahse it permits the gun pointer to water line his target. 15.Q.When is the longitudinal bubble on the sight used? A.Only. when using quadrant elevation in éighting by Case I and when testing the sight against the clinometer mounted on the bore rest. 16.Q.How often are pointing tests held? A.At least once each week a pointing test shall be made at the gun batteries of the primary armament.C.A.D.R.834. 17.Q.I1s any record made of the resultst How? What is done with it? A.For each trial,secords are kept on Ordnance Dept.form No.8l17 of the time from LOAD to FIRE,the range to the target,the time from READY to FIRE, and the deflection error; one cépy is forwarded to the post commander and one copy posted on the bulletin board of the compahy.C.A.D.R.536-1909. 18.Q.Describe the method of making this test in a gun battery of the primary armament andgive an example? aoe) 37 19.Q.How is the excellence of the gun pointer's work gaged? A,The excellence of the gun pointer'’s work is determined,first,by the accuracy of his pointing; second,by the promptness with which he is able to give the command FIRE after the piece is ready it in its Proove,exsrts practically uniform pressure avainst the telescope in every position. 7.Q.4y what means is the telescope elevated and cepresged? A.Ihe telescope,being pivoted on its hcrizontal axis,is movec in elevation and depression by means of the worm and worm rack,which are so made that one complete turn of the worm spindle moves the telescope about its horizontal agis thru one degree. 8.QeHow is the micrometer screw craduated? How is it adjusted? A.It is graduated to rend minutes from 0 to 60 minutes. It is provided on top with two amall screws which secure the collar on which the fraduations are made. After tinscrevins them the collar can be turned independently of the spindle and adjusted to make the micrometer readin; agree with the vernier reading. 2 9.Q.How is the vernier craduatec? How is it adjusted? A.isne least reaiinc of the vernier is 2 minutes. By means of the vernier eacn two minutes of the half decrees on the elevation arc may be accurately sct. ‘the vernier is attached to a vernier piece on the left side of the tclescope and is adjusted by teams of two screws workins into the vernie: piece,and against} two shoulder pieces bearing aguinst t’:e vernier. 10.Q.Describe the parts used in se*linc ceflection? A.for givince deflection a set of platinum cross wires,one verticul and one Orizontal,an’ two scales,ove insice and one outsice are prov:ced. she. vertical cross wire is attac'.ecd to a slidin. diaphram actuated by the deflection screw on tie right sice of th. telescope. In civine ceflection this vertical wire moves alons the interior horn scale and indicates the reu’in~. In addition,this diaphruem has a pointer which at the same tine moves alén: the outsice scale,givins: the reading without lookin; i-to the tel scope. The telescope is cut away at cthis place to make rvom for the outside scale,and to reveal the pointer. the screw actuctins t'¢ slidin, diaphrasmn is aceurateci, cut ‘%o civs correct reading,and t*e wack lash i. overcome by two spiral sprinss workin= against this © diaphragm. Ihe horizontal cross wir is attached to a fixed diaphragm placed behiuid . . the slidins onc.For **e purpose of acjustinont this diaphragm can Le riven a slisht motion in a vertical direction and securec in the correct position. 1.Q.How urc the insides and outsice deflection scales and the deflection screw rracuated? from -(9 derrec A.she insice scal¢é is grasunte. 20 5.ev decyrees,the least readin: veing .co degree. 3 decrees is cre normal of wie cale. the outside scale is crauduates from .oG cvzres to 5.50 desrees,the least reacing being .5¢ cecree. Three dovtrees is the normal of the scale. the deflection scriw is rracu..ted from © to .b0 degree. re least reacine is .Co devree. One turn of the screw moves the outside pointer and the vertical wire thru .50 dirrees of their scalcs. By means of the acflecition sere. te outside scale can Le read accuracely to .05 decree an’ cau ve estimatc closely to .OQl decree. 12.2.Describe the two levels and give the use of each! Aethe telescope level,fasicne” to the richt side of the telescope,is used only in Case I when quadrant elevation is set on tiie elevation scale,and in makin: adjus*ments when it Ls cesirec t@ level the telescope. The cross level is attachec to the uncersices of the celescope and is provicsd with an openin,, at “he top for direct layins,and one at the botton for reverse layine (when the objective is pointed to wre rear). Yo obtain a correct angle of elev tion che elevation arc must ce ver*‘ical. the purpose of the cross levcl is to maze the horizoutal axis of *~'.¢ LY telescope truly, horizontal so that vie elevaticn are will be vertical. L3.y.Mame the leuses in the vele cope in orser fron front to reart alL.Objective 2.1wo erecting prisms which cause the imaye to be seen right side up 3."ield lense,at the front end of th: cys piece 4.Eye lense. at the aperture in the eyc pieee. l¢.Q.Hor what qualities is this telescope especially desioned! aeLarce ficld of view,an erect inure,and *the maxisunm anount of Licht the cye will receive undcor the vost unfavorable conditio:.s. 1b.Q.v%at is the power and field of viewl , e e 3 a eC = ° aePowor is 4. the fiele of view is 6°79! L6.Q.H4ow ave the objective end eye piece focusect aeObjective,by a focusing collar buck of the sunshace. Eye piocs,dy screwilns or unscrewing it in its beurine. oe TISLYRUCLIOI FCR UstItu TH: oIvHr. L7.2.0heon should the siv~ht be removed from its case? A Mot until the cun pointer has reached the sighvi:.. platform. This will avoid any accideiut vhich might injure the sic’ t before it is placec ln its bracke:. . 18.Q.vhat other precautions must be taken in handlins the sight? A.While the sight is in the casc,the cover should be kept fastened. In rer.ovin: the sight from its casc,take hold of the strap; otherwise it is liable +o slip from the hands. L°.o.uhy is it inportant to ses that the objective is screvcd home before focusing the telescope . (ihe cell and rincs containin= the objective screw into the front end of the telescope), A.The optical center of the objecvive may not coincido with the axis of the screw at all psoitions. A change in the position of the optical center involves at once a chance in che line of sight. This may cause a large errore 20.Q.Describe the process of focusins the telescope? aAFirst with the telescope pointcd to the sky,focus the cye piece hy screwing or unscrewing till the cross wires,with every rouchness on wen, are distinctl, visible. Next focus the objective by directing the telescope on a distant object and turnins the focusing collar until, on shiftine the e,e over the e,e piece,the intersection of the cross wires remains on the same point of the object (there is then no parallax) EE 21.Q.uhat is parallax? A.For cefinition,method of removinz,and importance Sec Observer III (a) 4 detailec knowlecge of acjustment and use of all observine instruments and range fimders,questions 38 to 40 inclusive, page /-7S . 22.Q.iht is the trouble when the tarcet cannot be seen as distinctly} wnen parallax is removed as when some of it remains? Aethe distant obiect selected for this purpose sh-uld possess a sharp outline when the objective is focused. Should the image not be clearly defined,thon the eye piece is not correctly focused,and must be ara adjusted until th imace is clear. 23.Q.Do the objective and eve piece require focusing for each individual? Aethe eye piece does,but %.c¢ objective once focused is correct for all observers. Unless cisturbed,an objective once focused will remain so indefinitely. 24.Q.In what mamer should the sight be placed on its bracket? A.The sight trunnions should be carefully placed in the V'§ to avoid scratching or denting them. any chance in their shape will throw the sight out of adjusta:nt. he levelins lug should be brought to bear “sitll, against the levelin~ screw. 25.2."hy should the cross level bubvle be centered when aiming? A.eThe cross level must be centered so that the elevation arc will be vertical in using Case I, otherwise the angle of elevation set on the arc will not be a vertical angle and the elevation eiven to the gun will be less than intended. In usin; the vertical wire in Case II, unless the wire is vertical \it should be vertical when the cross level is centéred) there is apt to be a sight error in deflection due to the inclination of the wire. CARE AND PRESERVaLICN OF 1ELESCOPIC SIunH. 26.Q.Can a telescopic sicht stand rough usage? not aeNo. It is a delicate instrument and mst,be subjected to any roug usaze, jars,or strains. 27eQ.hy should the V bearings and trunnions be kept free from rust anc dirt? aeBecause a small amount of rust or dirt on either of them will be sufficient to throw the sisht out of acjustment. 28.Q.In what kind of a place shoul? the sight be kept? A. The sights mist,when not ir use,be kept in their leather cases in a dry place ° -_-. oS J0 29.Q.1n what co:dition stould the classes be kept? A.to obtain satisfactory vision,the classes should be kept perfoctl: clean and dry. Hither a piece of chamois skin or a clean linen handkerchicf will answer for cleaning purpose,care bcin: taken that the cleaniug materiel does not contain any dirt or grit which will scratch the elass. The glass will seldom require cleanings on tie inside; but, when necessary they should be unscrewed and cleaned by a competent person only. ‘the object glass losjective) should be kept screwed hone. 30.Q.\shat is prescrived by C.a,.D.R.1009, par 887 with reeard to teking apart telescopes? A.he prisms and lenses in the telescopes of position finders,azivuth instruments,ecn’ sights are not arransced for adjustmentb, those using them; the taxince apart of telescopes for any pur posef, and the mukinz of any adjustucuts other than those provided for in their constructim and described in the pamplots issued by the Ordnange Departme::t, except under the supervision of district armanecnt officers,are forbidc“en. wnen telescopes or any instruments of t!c ranre findine and fire control system for coast artillery issued by the Ordnance Department require 1 pair,a report describing the character anc exgent of the injurie: or defects is made to the armanent officer of the district. In cass the repairs or adjustiac.ts required ty tcolescopes and athcr delicate instrinci.ts of precision are of such a nature that they can not te made at the post the instruments are shippec by express %o such arsenal as may be desicnated by the district armament officer. 31.Q.How are the trunnions cared for? A.the trunrions are purposely left bricht. Sand paper or emery paper shoul. on no acc unt be used on these trunnions. a slight rubbing with crocus paper will remove rust from them. ‘the trunnions of the model of LE°S and 1898 Mo sichts arc made of phosphor-bronze which possesses sreat hardness,eélasticity and resistance to corrosion. These trm:uions are not as liable to rust as those on ot'.er models of sistt. a little vaseline shoule be kept on trunnions as 4 preventative of rust. 32.40. How are the worm and worm rack cared for? A.They should be kept oiled with a little machine oil 33.Q.280w should dust be removed fromthe cross wire? aABY a competent person only,usiuc a fine camel's hair brush. 34.0.Shnould any of the adjusting screws be touched? A.No,unl.ss by a competent person authorized by the Chief of Ordnance to make adjustncnts. This applies particularly to the screws h ldine the cross level,the deflection scale,the micrometer screws,and the vernier,!ut docs no: appl: to the screws for mukine the gracuation on the milled heacs of the elevatius screw ane deflection screw asree respectively with the vernier and with the interior deflection scal:. 46 35.Q.what core is treken of the bearings on wre bracket? aelthey snould be kept slishtly pyreasged to prevent rust,and «ll dust removed from them before the sich’ is seated. 30.Q.:hat should be ti. conditicn of the sight when put in its case? A.Lt shouvle be fre: from dust and moisture ani °::..:;: « little vaseline on the tru:..ions. 37. .gouny shuld sichts be inspected occasionally while stored in cases? A.Because the tan.ic acid in the leather case may affect the Lricht parts Ly of ch: clcht and cause corrosion. 38.y.uhnat must be the condition of che optical parts before any sight is tested? Aslhe objective an? cys plece lenses must te clean and the objec.ive screwec home to the point where its optical axis coincides with the axis of the screw thread. 39.Q.ho orcinarily replaces broken cross wires? «ill it ever have to be done by gun pointers? What is the metiod? A.the resident ordnance machinist usually replace: broken wires. Uncer service conditions it may easily happen that this will have to “c« done by, fun pointers. the method follows: In the models of 1898 and LE&Co@ M si, bts,after removing the cap contain- in~ the eye piece,unscrceyv tne three screws which fustcn the horizontal cross wire frame and re~ove this frame. shen unscrew the two screws which secure the horn deflection scale and remove it. Now unnook the two spiral sprinss which are attached to the end of the micrometer box and unscrew the knob fromthe deflection screw,vhen the slide can be removed. after renewing the cross wircs,replace the parts in the reverse order in vhich they were removed. the models of 1898 and 1898 M sights will require in addition an adjustment of the frame carrying the horizontal cross wirc, and perhaps an adjustment of the praduated ring, of deflection knob,a: explained in the cirections for adjustine these sights. Care should be had thu. %..¢ platinum wires lie in the bottom of the small grooves which are cut in the micrometer slice and frime to receive them; otherwise the, will not vo vertical and horizontal, respectively,when placed in the sight. 48. 2.How may a sight be testec with the facilities at a fortification? \ho makes such tests? A.eThese tests are always conducted by an officer or specially trained ordnance machinist. For tests and methods of conduct’ x= them for all modeks of sights,ses Appendix hy page (73. CUN COMMANDPR and Gtiy Porrern, VIII Pointing. (c) Emergency system and salvo points. For this subject,see the same subject under Plotter II (da), Yr Sits. Yo VIII (d) Bore sighting and orientation. 1.Q.Describe the process of bore sighting? Why should guns be bore sighted frequently! - A.Guns should be bore sighted frequently in ordér to check the adjustment of the sight standard and to correct it if necessary. The process is as follows; Place a bore sight in the breech and a thread in the vertical diameter of the muzzle. Sight thru the bore sight and bring the mzzle thread on a well defined point of an object at or beyond the mean range for-ithe niece, If a bore sight is not available the vent or a thread in the vertical diameter of the breech may be used. With the sight in ad justment on the sight bracket and the vertival wire set at normal,adjust the sigh- standard until the vertical wire of the signt is brought on the point. C.A.D.R.d2o. An improvement in this method which has been practiced by persons acquainted with it for several years and which was published in a circular letter from Headquarters,Hastern Division,Jan.18,1913,is as follows: Place one of the objectives of a field glass against the vent when the breech - is closed,the vertical wire being inthe usual place on the mzzle of the gun. The effect is to cause the wire to appear like the vertical hair in a telescope,and the accuracy in sighting is practically the same as if a telescope centered in the gun were used. A material increase in the accuracy and certainty of adjustment is thereby secured. See adjustment of Sight Standard under II Gun and carriage,page 33 , 7 - Soe . oO . St . . 2.Q.0n the disappearing carriage model 1898 for 6 inch gun,can the line of 4 sight be made to converge with the axis of the bore by adjustment of sight standard? A.No. (See Adjustment of Sight Standard,page33 . 33Q.0n this carriage,what can be accomplished by bore sighting? A.It may be determined whether or not the line of sight is parallel to the axis of the bore. If not parallel the error may be determined by measuring the error with the vertical wire and the deflection scale. In making this test for parallelism,converge the line of sight and the axis of the bore on a point at least 3 miles distant. Theoretically the two lines ecnnverging on such a point would not be parallel,but practically they may be considered parallel since they are sides of a triangle 3 miles long having a base of only a few feet, 4.Q.How may an error determined as above be corrected on this carriage? A.It cannot be corrected by adYjustment of sight standard. It would not be advisable to have the ordnance Dept.move the inside defleétion scale to correct the error because the sight would then be out of adjustment for use on any other carriage. The gun pointer or deflection recorder mist be trained to apply the correction to each deflection before it is set on the scale. If the vertical wire reads less than 3 (normal) when the gun is bore sighted the proper deflection for the gun pointer to set will be less than that sent from the deflection board by the difference between the reading when boresighted and 3. v9 In a similar manner,if the vertical wire reads more tnan 3 when the jun is voresi,uvea the proper deflection setrin, will ve greacer vnan that senue vy the aifference vev.ween the reauingg when pore- si,ntea anu 0. 3eQein bore sighting why is a point at or beyond mean range of the piece selecteds Draw a figure and explain? A.secause a point at mid range causes the line of sight and the axis of the bore prolonged to draw nearer each other till they cross at mid range,after which they gradually draw apart until at extreme range the distance between them is not greater than the distance between them at the gun. This gives a zero deflection error at mid range and a minimum error at short and long ranges. Even at these ranges this error is so small that it may be neglected. If any point between the battery and mid range is taken,the error at long ranges will be increased for two reasons; <= L. The line of sight and the axis of the bore make a larger angle with each other than before, 2. The error due to the divergence of the lines is equal and opposite to that at the mzzle,when a range is reached that is double the range of the point of intersection, and is proportionately greater as the distance from the point of intersection increases, It may at first appear that the advantage lies with a point of intersection at about 3/4 of the effective. range,since this unavoid- able error would then be a minimum where the effect of an error in deflection setting would be approaching the max&mmm. This error is too small to affect the probability of hitting the geheral target at long ranges,while at short ranges it might interfere with hitting selected vital parts of the target. For this reason the mid range point of intersection is undoubtedly best. 6.Q.What is meant by orientation in connection with a gun battery? A.(C.A.D.R. 1909 par.527) The proper setting of the azimth indices on the asimuth circles of the guns so that,when the guns are aimed at a point near the main channel about mid range from the battery,the asimth reading is the same for each; this reading to be the correct azimth of the distant point from the directing point or gun. 7eQ.Why is a point at mid range of the battery and near the main channel selected? A.Because if such point is used the azimuth differences due to gun displacement may be disregarded. 8.Q.If there are two channels of equal importance what point should be taken? A.A.point at mid range and mid way between the channels. 9.Q.What is the purpose of having the guns of a} battery orientated? A.So that,when Case III is used,the azimth of the target from the directing point,or gun,may be set on the azimth circles of both guns. 10.Q.Exphain why range dhfferences are stenciled on the base ring or on the step of the loading platform? A.See Fig. eset CLG L Es feu « Due to the displacement of the guns from the directing point,the range from either of the guns to the target will be different from the range from the directing point to the target,except when the target is on a line midway between the directing point and one of the guns and perpendicular to the line joining them. In this case the range from this gun to the target is the same as from the directing point to the target. The fire control system determines the range from the directing point to the target. To get the range from a gun to the tarret,the range setter mst add the number of yards nearest the indicator: if marked + and subtract if marked - . Usually each five yards of range difference is stenciled and marked + or ~ . A line called the indicator is stenciled at a convenient place on the carriage and indicates the range difference of the gun at any particular azimth. The numbers may be stenciled on the parapet wall and the muzzle used as an indicator. If one gun is taken as the directing gun,there will be no range difference for it,and only the range setter of the other gun will have to apply range differences. [ach him br parat anachid bun Sun tra GUN COM TANDER AND GUN POINTER, X1 Channels leading to harbor. (Note: This is in Part V of the examination for Observer). 1.Q.What is the meaning of the word,"harbor",in the sense that it is used here? . A.Al1 of the navigable water area within or behind the zone of protection of the fortifications. It does not mean the harbor of any particular seaport when more than one are located with- in or behind the defended area. For instance the Coast Defense of Long Island Sound defends the whole Sound and the many ports which are dependent upon it. 2.Q.What are the names of the bodies of land on which the forts of this coast defense are located? A.Fort H.G.Wright,N.Y.,on Fisher's IslandjFort Terry,N.Y.,on Plum Taland;*ort Wichie,N.Y.,on Great Gull Island, Fort Mansfield, R.I.,on Navatree Point;"ort Tyler N.Y. ,on Gardiner's Point Shoal. (Note:Underlined parts of answers to be left blank in printing under this and the following questions). 5.Q.What is the name of the main channel leading to this harbor? A.The Race, so called because of the very swift currents found in it on each chanze of tide 4.Q.Where is it located? A.In general, between Fort Michie and Fort H.G.Wright. Strictly speaking, between Little Gull Island near Fort Michie and Race Rock near Fort H.G.Wright. 5.Q.What are the names of the lighthouses covering this channel? A.Little Gull Island light and Race Rock light. 6.Q.What is the least depth of water in this channel’? A.35 fathoms or 210 feet between Race Rock and Valiant Rock. 28 fathoms or 168 feet between Little Gull Island and Valiant Rock. ) 7.Q.What classes of warships can navigate it with safety? A.All classes. 8.Q.Are there any natural obstacles in or near it which would make its navigation at night, or in a fog, with aids to navigation removed, dangerous to navigators unacquainted With it. F2 A.Yes. The Valiant Rock which is submerged under 18 feet of water at mean low tide and which is situated about midway between Little Gull Island and Race Rock. The cross currents and eddies would also be dangerous. 9.Q.What is the name cf the second best channel leading to this harbor? A.Plum Gut. 10.Q.Where is it located? A.Between Plum Island and Orient Point, the nearest point of Long Island. It is located just beyond what is known as e New Harbor at Fort Terry. 11.Q.What are the names of the light houses covering it? A.Orient Point Light in the Gut near Orient Point and Plum Island Light on Plum Island. 12.Q.What is the least depth of water in this channel? A.9 fathoms or 54 feet either side of the middle ground. 13.90.What classes of ships can navigate it with safety? A.All classes. aw 14.Q.Are there any natural obstacles in or near it which would make its navigation, dangerous to navigators unacquainted With it. A.Yes. The middle ground on the line between the light houses has but 19 feet of water unon it. Midway Shoal with the same depth of water over it rune from Orient Point light toward ine Point,the southern point of Plum Island. 15.Q.What is the name of the channel between Great Gull Ialand and Plum Island? A.Gull Island Channel. 16 .Q.In what part of the water area between Plum Island and Great Gull Island is the channel located? A.About 1000 yards closer to Great Gull Island than Old Silas Rock;i.e.e700 yards from F'6 and 1900 yards from Fort Michie dock. 17.Q.Are there any light houses covering it. A.No,not directly. Little Gull Island light would be of assiatance in navigating it. wr ee ee ee Se oe eS eee 18.Q.What is the least depth of water in this channel? A.25 feet. 19.Q.What classes of warships can navigate it with safety? A.Al1 classes at high tides with skilled pilots,who have an intimate knowledce of the channel and currents. Under other conditions only light draft ships could afford to attempt it. - 20.Q.What are the natural obstacles in or near it which would make its navigation at night, or in a fog, with aids to navigation removed, dangerous to navigators unacquainted with it. A.Old Silas Rock, usually quite well exposed, is 1000 yards nearer Plum Island. Half way between the channel and Old ee ee ee ee -_— = Silas Rock is a submerged rock having but three feet of water over it. On the N.E.side of this channel, 1500 yards from Old Silas Rock and in prolongation of the line, ast End of Plum Island-Old Silas Rock is a small shoal under 18 feet of water. Toward Great Gull Island is rapidly shoaling water. The area immediately S.E.of Old Silas Rock is occupied by Middle Shoal under 19 feet of water, 1500 ~ yards South of Old Silas Rock is Bedford Shoal under 15 eet of water. The preatest depth between Fast End of Plum Tsland and Old Silas Rock is 1” feet. No channel exists here. 21.9.What is the name of the channel between Plum Island and Sardiners Point? A. No name is given on the charts but it is customary to refer to it as Gardiners Bay Entrance. e2.Q.What are the names of the light houses covering this channel? A.There are none. Distant lights furnish range lights to aid navigation. 23.Q.What is the least depth of water in this channel? A.About 12 fathoms or 72 feet. 24.Q.What class of warships can navigate it with safety? A.All classes. 25.Q.Are there any natural obstacles in or near it which would make its navigation at night, or in a fog, with aids to navigation removed, dangerous to navigators unacquainted with it. A.Not in the immediate vicinity of the channel but Constellation Rock,under 1” feet of water and situated about #500. yards E.W.E.of the channél and Plum Island Rock opposite the bath houses at Fort Terry are a menace to navigation. 26.Q.Yhat is the name of the channel between Fisher's Island and Napatree Point? A.The charts give no general name but each passage between the reef joining Fisher's Island and Watch Mill is named: atch Hill Passage,Sugar Reef Passage ,Catumb Passage, Lords Reef Passage and Wiconesset Passage. go ~ 27.Q.What is the width cf this channel? A.From Napatree Point Ledge to Wicopesset Rock is 1600 yards. ugar Reef Passage is about 500 yards wide. ~~. em ee Oe ww 68.Q.What are the names of the lighthouses covering this channel? A.Watch Hill Light and Latimer Reef Light. 29.Q.What is the least depth of water in this channel? A.2l feet in Watch Hill Passage; 35 feet in Sugar Reef Passage; ee feet in Catumb Passage; 39 feet in Lord's Passage; 19 feet in Wicopesset Passage. 50.Q.What class of warships can navicate it with safety? A.Lord's Passage and Sugar Reef Passage can be navigated by all —-—_e = oS >. classes. The others are confined and full of short turns. 31.Q.Are there any natural obstacles in or near it which would make its navigation at night, or in a fog, with aids to navigation removed, dangerous to navigators unacquainted With it? A.Yes there are many submerged rocks and shoals in the immediate -_— ws oe vicinity of the passages and in Fisher's Tsland Sound. SF 32.Q.\hat is the name of the body of water northwest of Plum Island and west of Fisher's Island: A.Lone Island Sound. 33.Q.What is the name of the body of water southeast of Fisher's Island and east of Plum Island? A.Block Island Sound, 34.Q.What is the name of the boay of water south of Plum Island? A.Gardiner's Bay, 35.Q.What is the name of the body of water north of Fisher's Islana? AeFisher‘s Island Sound. 36.Q.what headlands or points are visible from Fort verry! LONG ISLANDS HEADLANDS. A.ifontauk Point at the extreme end of Long Island; Shagwong Point just leaves Montauk Point exposed; Culloden Point with a prominent group of three buildings upon it, is on the east side of Fort Pona Bay; nocky Point ts separated from Culloden Point by Fort Pond Bay and - marked by a low conical hill stunaing in front of higher ground to the south and southwest; , GARDINER'S ISLAND HEADLANDS. Eastern Plain Point marks the east end of Gardiner's Island; Gardiner's Point on which Fort ‘iyler is located; Crow Head the high tan colored blutf,which marks the west end of Gardiner's Island; LONG ISLAND HEADLANDS. Hog Creek Point,with three prominent buildings regularly spaced upon it,on Long Island, just west of Crow Head; Cedar Point on the east side of Sag Harbor entrance; SHELLER ISLAND teapLANDs, Mashomack Point on the west side of Sag Harbor entrance and beyond Cedar Point; Nicholls Point on the west side of Sag Harbor entrance and closer itinan Cecar Point; RaM ISLaiiD HEADLAND. Ram Head,north of Cedar Point and in front of Shelter Islana; LOWs ISL:ND nEaDLAND, Long peach Point,south of the town of Orient and on the north side of the channel leading to ureenport; PLUM ISLAND nEADLAND. Pine Point,the southern end of Plum Island; LONG ISLAND nEADLAND. Orient Point,opnosite the New Harbor; CONNECTICUT HEADLANDS. Hatchett Point,west of slack Point; Black Point,on the west side of Niantic Lay; Mill Stone Point, betweon Niantic bay and White stone Creek and directly north of Hast End of Plum Island; Eastern Point on the eastern side of New London Harbor; #ISnER'S ISLAND HEADLANDS. Race Point,the western extremity of #isher's Island; Wilderness Point just to the east of Race Point. 37.Qehat lisht houses and light ships can be seen from Fort ‘erry? see a’. a t: ~xle below. LIGHiHOUSZIS. NAMIE vHANACTER INahiVaL COLOR C? HETGha VISIBILITY PROM PAS Flash'g Bet.Flash.Structure above lVautical DTS. aNncrk. PinScc. sca Ft. Biles Cedar tixed Island Whiie Granite 45 11 10 Lon:: Fixed Beach Bar Red vhite 54 81/2 8 Orient rixed Point Red Brown 64 11 1/4 3 Plun elash's Islené White O T71, Veiite 76 14 265 Meu, Lonc on ~ixed Harbor Rec wiLte SO 15 8.3 North rixed Dinplin: White vmite 70 1/2 11. &.9 Race Flasn's 0 1 Granite 681/2 14 6.1 Rock Red aud Waite Little Fixed Gull I. ‘white Granite 92 17 208 lfontauk Flash'¢ “White with 169 1/2 19 1/4 15 1/2 Point White Oo 10 Brown band LIvHi' VESSELS. MAT oS COLOR OF HULL Mails SORE AST NATIT AS 'L LIGH'S HULL Bartlett slack Vords"Bartlett Black cage Black c:.e Reef with neef" Light “Ihnite Vessel Streak END AZIMULH. 26 248° 297 2 Fixed ‘white. GENERAL FeaTURisS OF waroHIps BAL TLESHIPS L.Q.iwhat is the purpose of a battleship? A.To fight the heaviest ships of the enemy in line of battle. 2.Q.What is meant by pre-Draednoughts, Dreadnouchts, and super-Dreadnouchtst A.The Dreadnought was a British battleship built in 1906 which made a great change in the size and construction of warships because it was built on the "all-big-gun principle.” Battleships built before the Draadnought are called pre-Dreadnoughts and are rated as having but moderate power in battle. Dreadnoughts are warships having about the same qualities as the Dreadnought. Super-Dreadnoughts are ships having greater power than the Dreadnought. American examples of each type are as follows: | Pre-Dreadnought Vermont and Louisana classes Dreadnought Michigan and South Carolina Su per-Dreadnoughit Arkansas anc Oklahoma classes 3.Q.What is the usual length of battleships? A.Pre-Dreadnoughts 360 to 485 feet. Dreadnoughts 490 to 580 feet. Super-Dreadnoughts 820 to nearly 700 feet. 4.Q.What is the beam and draft? beam Draft. A.Pre—Dreadnoughts About 76 feet 2% to 28 feet Dreadnoughts "89 ° 24 to 31 ” Super-Dreadnoughts 80 to 97.5 26 to 29 " 5.Q.What is the usual displacement? A.Pre-Dreadnoughts 10000 to 16000 tons. Dreadnoughts 16000 to 18000 " Super-Dreadnoughts 18000 to 32000 " 6.Q.What is the usual speed? A.Pre-Dreadnoughts 15 to 19 knots. Dreadnoughts 19 to 2." Super-Dreadnoughts 80 to 245 ” 7.Q.How much motive power does a battleship usually have: A.Pre-Dreadnoughts 9000 to 17000 horse power. Dreadnoughts 16500 to 23000 ” n Super-Dreadnoughts 20000 to 40000 " n 8.Q.What guns does a battleship carry? A.Pre-Dreadnoughts 4-12 inch,about 8-8 inch and a number of smaller guns. Dreadnoughts 8 to 10-12 inch,and &0 or more 3 inch guns. Super-Dreadnoughts 10 to 14-12 to:.14 inch puns: and 20: or more 5 to 6 inch guné, 9.Q.How many turrets does a battleship carry? A.Pre-Dreadnoughts 2 large 2 to 8 small Dreadnoughts - 4 to 5 large Super—Dreadnoughts 4 to 6 large 10.Q.What armor does a battleship carry? F. S. Belt | Casemate iurrets Barbettes Conning |. A. Pre-Dreadnoughts 8 to 9 5 to 8 8to12 5 tol? 7 to 14 Dreadnoughts 9" 12 8@"12 eae" 12 10" 11 12 Super-Dreadnoughts 9 " 12 8 "12 18" lo 9" 14 12 11.Q.How many funnels does a battleship usually carry? A, Pre-Dreadnoughts 2 to 3 funnels Dreadnoughts 2 " Super~Dreadnoughts 1 to 2 " See table of Battleships on ge BALLLE CRUISERS 12,.Q.What is a battle cruiser? A.It is a type of ship designed immediately after the British Dreadnought of 1906. It so improved the armored cruiser type by increasing gun power,armor protection,and speed that they were capable of overtaking and destroying the fastest armor cruisers. Battle oruisers are almost the equals of Dreadnought and super-Dreadnought battleships in gun power and armor protection,and are mich superior in speed. The battle cruiser is longer,narrower,has more displacement usually,a mich greater motive power and one less big gun turret than a battleship of the same date, The U.S.Navy has no ships of this type. The British Lion,and Invincible and the German Moltke and Vonfier Zann are examples of this type. 13.Q.What is the usual length of battle cruisers? A.Moltke 590 feet,Invincible 560 feet,Lion 596 feet. 14.Q.What is the beam and draft? A.Moltke beam 76 draft 26 feet,Invincible beam 78 draft 27/ feet. Lion beam 86 draft 27 feet. ed 15.Q.What is the usual displacement? A.Moltke ,22500 tons ,Invincible ,17250 tons,Lion,&5000 tons. 16.Q.What is the usual speed? A.Moltke,28 knots,Invincible ,28 knots,Lion 29.5 knots. 17.Q.How much motive power does a battle cruiser usually have! A,The Moltke 8§%O horse power,Invincible 41000 horse power,Lion 70000 horse power. 18.Q.What guns does a battle cruiser usually carry? A.See table of Armored and Battle cruisers, fag bY Ge 7S 19.Q.How many turrets does a battle cruiser carry? A.About four. Usually one turret less than the battle shins bilt at the same date. 20.Q.What armor does a battle cruiser carry? A.See table of Armored and Sattle cruisers 21.Q.How many funnels does a battle cruiser usually carry? A.Moltke, 2 funnels Invincible 3 " Lion 3 «O" ARMORED CRUISERS 22.Q.What is an armored cruiser? A.It is a type of ship designed and built from about 189.5 to 1906 as a destroyer of the enemy's protected cruisers,for the protection of the merchant marine of the nation to which they belonged,and for "flying squadron" duty;i,e,,for making sudden dashes upon the enemy. 23.Q.What are its characteristics? A.Great length,narrow beam,high freeboard,three or four funnels,large motive power plant,great coal capacity,moderate armor protection and medium guns. 24.Q.What is the usual length of an armored cruiser? A.From 400 to 600 feet. 25.Q.What is the beam and draft? A.ithe beam from 40 to 70; draft from 23 to 48 feet. 26.Q.What is the usual displacement? A.From 9000 to 16000 tons. 27.Q.What is the usual speed? A.From 19 to 2 knots. 28.Q.How mich motive power does an armored cruiser usually have? A.From 12000 to 32000 horse power. 29.Q.What guns does an armored cruiser carry? A.ithey usually carry 4-8 to 10 inch and a variable number of smaller guns. 30.Q.What armor does an armored cruiser usually carry? A.Belt 4 inches,barbettes 4 to 7 inches,and conning tower 5 to 12 inches. 31.Q.How many funnels does an armored cruiser usually carry? A.From 2 to 4 funnels. 32.Q.Are any nations building armored cruisers to-day? A.No. Some authorities refer to the battle cruiser as a modern armored cruiser,others make &he distinction that an armored cruiser is one having particularly guns smaller in caliber than battleships of the sane date as well as the usual differences of lighter armor and greater speed. the latter authorities define the battle cruiser as an improved armored cruiser having guns of the same caliber as battleships of the same date but usually about one turret or two guns less in the main battery. All nations building the cruiser type are building this la$ter type. See table of Armored and Battle cruisers on pages 45297." SHIP Massachusetts Royal Sovericn Heimdall vanso Georria Louisana Kins Edware Braunschweifr Kashima Mi chizan Dreacnouynt “iestfalen satsuma Delaware Neptune Relczoland Aki Arkansas Orion Kawachi Texas BALILESHIPS. NaLlIONALITyY British U.S. German Japanese U.S. U.od. Britisna German Japanese U.S. Britisn German Japanese U.d. Britisy Moe ae Woelman Japancse Uv. british Japanese U.s. LAU? CHED 1893 L891 18S2 LEO DIMENSIONS. WALERT TIS LENGTH BEAM 358 69.33 380 To 267 48.75 367 o9 435 76.17 490 76.83 435 78 410 72 495 7 17 450 €6.29 520 82 470 89 479 83.5 910 €5.29 540 86 406 o 492 94 96a 93.17 528 Bu 479 86 573 95 ft. DRA. 28 ft. BATILESHIPS. NORMAL SPEED HORSE FUEL CAPACT iY SHIP DISPLACE MTT DESIGNED b'St POWER NORMAL MAX, FUNNELS. Massachusetts 10288 tons 17-knots 9000 400 1800-tons 2 Royal Soverign 14100 15 lo.lL 9000 900 1400 2 Heimdall 410¢ 15 16.1 5000 (580 2 400-oil ‘Tango L1C00 16 17 S000 700 1050 2 Georgia 14948 19 19.594 159000 900 1700 3 Louisana L6000 18 19.02 16500 900 2200 3 King Edward 163.0 18.9 19.1 18000 990 2156 2 40¢-oil Braunsehweig 13200 18 18.6 16070 700 L600 3 . 200-oil1 Kashima 16400 18.5 20.22 17¢6c0 i fo) 0-10 1010) a Michigan 16200 19 20.01 16500 90C 22C0 2 Dreadnought 1L790C 21 21.3 23000 900 2000 2 Westfalen 18500 19.5 20.4 aoocc 950 27c0 2 200-0i1 Satauma 192.0 20 18506 1000 2500 2 Delaware 20300 21 22,25 25000 1016 2340 a 600-o0il1 Neptune 20600 21 25000 900 2700 2 Helgoland 21000 20.5 950 2700 2 200-011 Aki 19750 20.5 25000 LOoc §=—._- 2500 a Arkansas 26400 20.5 21.3 33000 1933 3000 2 600-oil Orion 23000 a+ 27CCC 900 2700 2 LOC O-oil Xawachi 20750 20 26506 2900 3 ‘le Xas 27CG0 21 2 SHIP MassachuscGcits Koyal Soverign Heimdall Tanco Georcia Louisana King Bdward Braunschweic Kashima Michigan Dreadnoucht Westfalen Satsuma Delaware Neptune Helgoland Aki Arkansas Orion Kawacni Texas Donp poy rss sal aa ths ing WO anal liT ---Mumbcr of each Caliber, 16 15 2443.5 46 ll do $.2 € 7.59 7 6 5 4,7 L3 " 4 4 9.4” LO LZ LC LO L2 10 14 LO 8 1c 12 L2 - as Lo 14 tS to L2 21 20 12 p! vt) to © - to 27 Lé os BalsLESnuIPs, ARMOR wHiiCraviss IN INCHES. LURKEVS CASEMALS BaRbeTis -LAKGE SMALL CONMING SHIP BELL LOWE UPPER OK WUaREYBASES FaCE SIDS PACE TOWER Massachusetts 18-16" 5" 17" 8.5. 5” 6" 10" Royal Sovcrizgn 18-16 6 3 ' 17 14 Heimdall 9 .5-6 8 7 Tanco 15 5 9 | 10 5 12 Georcia 11-4 6 6 10to7 1208 9 Louisana 11-4 7 2 12 12 lo 6 9 Kin, Edwara 9-2 8 7 12 8 7 12 Braunschweig 9-4 4 9 11 ll 6.75. 12 Kashima 0-6 .5 . 6 9 to 5 9 8-6 9 Michigan 14-1.5 - 12-8 10-8 12 8 12 Dreadnought 11-6 11 11 8 12 Westfalen 9,275. 1o 4 11 12 12 Satsuma 9-4 8 12 8 8 Delaware 11 8 5 9-8 «42g Neptune 12 12-4 12-4 L2 12 L2 LZ Hele oland C.75 Ll lz ‘Aki 9-4 8 12 8 7 Arkansas il 11 8 10 12 Orion l2 12 Kawachi 12-5 Texas 12-10 11-9 6.5 14 14 8 12 SHIP King George V Oklahoma Iron Duke Warspite Konig Albert Pennsylvania SHIP King George V Oklahoma Iron Duke Wars pite Konig Albert Pennsylvania LALES£ BATTLESHIPS. DIMENSIONS NALIONALITY LAUNCHED LENGTH BEAM DRAFT British 1912 564 89—Ss«7.75 U.S. 1913 570 «95—ts«RLS British 1923 580 90 British 1923 German 1913 564.3 95.3 27.3 U.S. 1914 600 97 28.6 SPEED HORSE- FUEL CAPACILY DESIGNED BES: § POWER NORMAL MAX, knots. 31000 900 8700 20 1/2 22 33000 a5 21 2500 1000 3600 2 | NORMAL DISPLACEMEN: 88606 27500 25400 24500 FUNNELS. 1000-011 2 LATES! BALTLESHIPS, ARMAMEN tt =-Number of ecah Caliber SHIP 16" 15" 14" 13.5" 12" 11" 10" 9.2" 8" 7.5" 7" 6" 5" 4.7°4" 3" King George V 10 Oklahoma LO Iron Duke LO Warspite 8 Konig Albert 12 Pennsylvania L2 ARMOR <=thickmess in inches. CASEMAL'E | SHIP BELT LOWER UPPER BARBE‘‘'S King George V 12" 9" Oklahoma 13.5" 13” Iron Duke 12" Warspite Konig Albert Pennsylvania 16" 16 14 16 4 5.9" | 14 22 TURREZS Connin,, FACE SIDE S.#ACE TOWER 12" 12" 16” 10" 12" 12" ARMORED AND BATTLE CRUISERS DEMENSIONS. NORMAL SHIP NALIONALI1Y LAUNCHED LENUGTH + BEAM ... DRAFL DISPLACEMENT Saratoga Used. 1891 380 64 28 8200 Edgar British 1890 360 60 26 7350 Kaiserin- Augusta German 1892 388 49 25.5 6300 Chiyoda Japanese 1890 308 43 17 2450 St Louis U.S. 1905 423 65 23.25 9700 Diadem British 1896 450 69 27 425 11000 Roon German 1903 403 .25 65.5 25.75 900 Kasuga Japanese 1903 357 61.5 25 4&5 7750 California U.S. 1904 502 70 26.5 13400 Duke of- Edinburgh British 190% 480 73.5 27.9 — 13550 Schannhorst German 1960 »«=— 449.75 71 25 11600 ‘sukuba Japanese L909 440 75 26 13750 Washing ton U.S. L90u 502 73. 26.5 14500 Warrior British 190. 460 73.5 27.5 13550 Bluecher German 1908 489 80.33 27 15500 Kurama Japanese 1907 450 75.5 26 14620 Invincible British 1907 300 78.5 172.0 Lion British 1910 656 86.5 27.5 25000 Moltke German 1910 990.5 88 28 21800 +Takao Japanese 1911 541 80 26.5 18050 ARMOREL -AND BAYTLE CRUISERS SPEED DESIGNED KUEL CAPACI.sY SHIP DESIGNED bES1 HORES=-POWER NORMAL MAX, FUNNELS. Saratoga 21 kts,21 kts. 16500 750 1150 3 Edgar 18.5 19.5 12000 820 =-:1230 Kaiserin- Augusta 20.7 22.5 12000 $00 Chiyoda 19 5500 330 420 §t Louis 21.5 22 4 21000 600 1500 Diadem 20.25 18. 16500 L000 2000 400-011 Roon 21 21.4 19000 750 1600 200~0i1 Kasuga 20 19.8 13500 640 1100 Calfornia 22 22.5 23000 900 2000 Duke of- 2000 Edinburgh 22.33 22,5 23500 LOOO0 400-011 Scharnhorst 226 24.8 26000 800 389000 200-o0il Tsukuba 20.5 21 20200 600 2000 Washington 22 22.48 23000 900 2000 Warrior 22.33 23.1 23500 1000: 2000 +«00-oil _ Bluecher 24.3 26 4 32000 900 4300 200-011 Kurama 21.85 22.17 2000 600 2000 Invincible 25 28.4 41000 1000 3000-011 Lion 28 70000 1000 2500-011 Moltke 28 80000 L000 2500-011 ‘Takao 25 42000 ARMORE.: AND BATTLE CRUISERS ARMAMEWN tt -Number of each Caliber. SHIP 16" 15" 14” 13.5" 12” 11” 10" 9.2" 8" 7.5" 7" 6" 5" 4.7" 4" 3° Saratoga 4 LO 8 Edgar a 10 Kaiserin- Augusta 12 8 Chiyoda 10 St Louis 14 18 Diadem 16 14 Roon 8.2” 4 LO 14 Kasuga 4 14 10 California 4 14 18 Duke of - Edinburgh 6 10 Scharnhorst 8.2" 8 6 20 Tsukuba 4 12 12 4 Washing ton 4 16 23 Warrior 6 4 Bluecher 8.2" 12 8 16 Kurama 4 8 12 4 Invincible 8 16 Lion 8 20 Moltke 12.2” 8 6.7" 12 16 Takao 10 8 LO ARMORE: AND BATTLE CRUISERS ARMAMEN?Y -Number of each Caliber. SHIP 16" 15" 14" 13.5" 22” 11" 10" 9.2" 8" 7.5" 7" 6” 5" a.7" 4" 3" Baratoga 4 LO 8 Edgar a 10 Kaiserin- Augusta 12 8 Chiyoda 10 st Louis 14 18 Diadem 16 14 Roon 8.2" 4 10 14 Kasuga 4 14 10 California 4 14 18 Duke of - Edinburgh 6 10 Scharnhorst 8.2" 8 6 20 Tsukuba 4 12 «(12 4 Washing ton 4 16 23 Viarrior 6 4 Bluecher 8.2" 12 8 16 Kurama 4 8 12 4 Invincible 8 16 Lion 8 20 Moltke 12.2" 8 6.7" 12 16 Takao LO 8 10 SHIP Saratoga Edgar Kaiserin_ Augusta Chiyoda St Louis Diadem Roon Kasuga California Duke of - Edinburgh Scharnhorst. Tsukuba Washing ton Warrior Bluecher Kurama Invincible Lion Moltke Takao BELL 4" 9=3 4,5" 4? 4-3" 6-1 .5 6-3 .5 6-3 6~4 14 5-3 o-3 6-4 7-4 6 .290-4 70-4 CASEMALE LOWER UPPER 6" 4 & 6 4 4 6 6 6 3° 6 6 6 9 3 9 6 6 3 ° 8 ARMORE! AND BATTLE CRUISERS IURRELBASE 1 URRET S pARDE:TS ACE SIDE S.H#ACE 10” 7 rT 7 Guns in sponsons. Guns behind shields 4 6 260 99 4 6.5 7 6 6 6 7 7 7 9 7 8 6 7 7 LO 8 10 ie 4.75 9-5 12 U.S. AR'Y CASLE SHIPS. Qedhat is a cavle ship: By whom is it manned and operated! A.A ship designed for the laying and repair of submarine cable, nc ship is supplied and the civilian officers and crew are employed by the Quartermaster Corps, Each ship is under the command of an officer of the Signal Corps,U.S.Army. All work is performed by the shipn's crew under the direction of the commanding officer. QeWhat are the distinguishing features of cable ships? A.The distinguishing featureg of a cable ship is markec projectién at the bow or stem in which is mounted a large cable sheave over which the cable is paid out or wound in, Otherwise the smaller ships look mich like mine planters, All cable ships are now equipped with wireless. Q. what are the names,size,and stations of the Army cable ships. A. Names | | Tonnage Where employed : ' Gross Net. Burnside —_ - _ + 2194 1405 Pacific and Alaskan Coast. Cyrus W.Field 235 146 Atlantic Coast. Joseph Henry | 60lL 409 Atlantic and Gulf Coast. The burnside is an Army transport employed solely on cable work in the harbor of the Pacific Coast of the United States and more particularly on the Alaskan submarine cable. U.S. ARYY MII PLANTERS. Q.What are the distinctive characteristics of a mine planter? a.It¥ is painted with the government standard colors like navy tugs and tenders,cozus. snd geodetic survey ships,fish commission ships,army trans- potts,harbor boats of the Quartermaster Corps,boats of the Engineer Dept., U.S.Army ,etc. It has one funnel and two masts,the formast being used as the post of a nuderrick with three booms. Some have now discarded two of the booms. hen the booms are not in use they are usually secured in a horizontal position During the mine planting season there are also three davits,carrying differential blocks,along the rail on each side just forward of the foremast. An extensiom bridse at the pilot house over hangs the sides of the ship. she upper cabins are perhaps the most distinctive feature of all. Abaft the pilot house are cabins for the ships officers. Abaft the main mast is the commanding officer's cabin. There is considerable deck space abaft this cabin and still more abaft the lower cabin. this latter space and the large deck spuce forward are designed to afford plenty of space for handling mine material: while Q.By whom is a mine planter manned and operated? A.The ship is supplied and the civilian ship's officers and crew are employed by the Quartermaster Corps. Each ship is under the comnand of an officer of the Coast Artillery Corps. The ship's officers and crew are the nav=- igating force. The commanding officer,assisted by a detachment of about 20 enlisted men from some mine company,is charged with the planting and taking up of mines and the maintenance of mine fields, Q.What are the names,sizes,and places of employment of the army mine planters? ea ee uvross--lonnage--Net ‘here Employed. A.Col.George Armistead 4-27 304 San Francisco,Cal. San Diego Cal. Major Samuel Rin sold +47 304 Puget Sound, and Columbia River. Gen.Henry J.Hunt 447 304 Manila,P.I. Gen.Henry Knox +47 304 Manila,P.I. Geh.Samuel M.Mills o€O 401 Fort Monroe,Va. Gen.John M.Schofield 990 401 Atlantic and Gulf. Gen.Edward 0,C.Ord 990 4o0L Atlantic and Gulf. Gen. Royal ‘. Frank 990 401 Atlantic and Gulf. 4 a To tat ear "oor mound Ua .7! aOR Ha BOw BCat's . e qeHov Mas quarteomaste > boats are assi ned *o tuis Coast Defense? wout are their nanest AeFour, The voussal Natianael Creene,the General J.°'.Braimian,t!.c Geieral Robt.»e.yres,aid the Capt.Ciarles 1/.Rowell, qevnac are the features by which these ships can be distinsuisned from each ovner?s | .. Tonnare AsShip Leneth ospeeu Gross Net Distinguishins Features. Greene __139_ __ 12 340 210 2 masts. Dec): house flush with ruil in the waist. No deck space abaft tue cabin. 4 life baats. Brannan 98 ¢1/2 153 104 1 mast. Tug boat type of deck houses, Moderate deck space abaft the cabins, 2 life boats. Flap staff at ster on rail. Boom shorter than on ayres, 3 Windows and 1 door on starboard side 4 of officers’ cabin,4 windows on port side. No railing around top of pilot house and officers cabin. Glass in Pilot house door, Aluminum paint on whistle. ood cover on port life boat painted buff. Unpainted canvas cover on starboard life boat. Ships rail painted red. Cowls vermilion inside. _ Ayres 98 ¢ 1/2 153104 1 mast. ‘ug boat type of deck house, Moderate deck space abaft the cabin, 2 life boets covered with unpainted canvas. Flas staf? at stern of cabin. after stavs on mast removed. Pilot house doors and cabin vindovs the sare as on the Branzan. Fi ] around top of pilot house and rofficers'cabin. Shining brass whistle. Ships rail varnished. Cowls vernilion inside.Boom lonrer than on Brannan. Kowell 86 9 1/4 128 89675 1 mast. Tug boat type of deck house, Comparatively larse deck space abaft_ . the cabin. 1 life boat. Flap staff at, stern on rail. After stays on mast removed. .Jackstaff and flagstaff painted white. Cowls lirht green inside. No glass in pilot house door, Two Windows only on either side of cabin. Q-How can these ships be distinguished from commercial ships of the same size? A.All Quartermaster boats are required to be painted the standard government ‘ color and when under way in day licht to fly the Union Jaek at the jack shaff, she National Flag at the flag staff and the Quartermaster Corps flag at the main, except that when an officer entitled to a flag is aboard,his flac is ~~ ow ee ee 45 I Definitions C.A.LDLR, See questions indicated in "PLOTTER® column in annendix A. A ar ; 2 Eleaentry gunnery definitions are illustrated on Flementry Gunnery and “Nar3hics diagram under Plotter IV Elenentry Sunnery (a) Explanation of the several corrections to be applied to the observed range to cbtain the corrected range,facing rape £3 . > thaid be. ES [apse 76 B51 enigtlaeet Ae PLOTTER II #IRE CONTROL SYSTEM (b) Indication and Identification of 1sargets. This is subject II (b) in the examination for Observers, alsoCandidates for Gun Commander and wun Pointer ratings mst be proficient in so much of this subject as pertains to their ow duties and should be required to have a sufficiently general knowledge of the duties of the plotter and observers under this heading as will permit them to act intelligently in conjunction with the others. To avoid unnecessary separation of like material or repetition,some matter is placed here which could be placed under V Service of the Piece (a) Duties of Gun Pointer or XI Characteristic features of the several classes of warships etc. 1.Q.What is meant by “indication of a target"? A.Any method employed to designate a target. C.A.D.R.137 2.Q.What is meant by “identification of a target"? A.The act of process of recégnizing a target which has been designated. C.A.D.R.133 3.Q.What methoas may a battle commander use in the day time to indicate targets to his fire and mine commanders? A.During the day the battle commander need indicate the target in a generai way only,no attempt being made to give the exact location of the ship or ships by range and azimth. If two or more squadrons enter the battle area,a particular one may be indicated to the fire commander by its relative position. \ihen the squadrons are in different well know channels they may be indicated as tne squadron or vessels in__ -_ ~ channel. When the attacring ships are in well defined colum they may be indicated by their position in the colum, C.A.D.R. 576. 4.Q.What methods does he use at night! A.sargets may be indicated at night by means of the search lightg,a battle commander indicating a target to the fire commander by coverinc it with a searchlignt. she battle commander may cause a target to be illuminatec and followed by some light,and direct any particular fire commander or all of the fire commanders to open fire on such a target. C.A.D.R. 577. 5.Q.When a fire commander desires to indicate a tarcet to his observer at ¥" ,what methods does he use? A.ahe same as tose prescrived for se use of a battery commuandor. See question 9 Lelow. ot 6.Q.How does a fire coimiwnieer insicute a tar et to his patter; com arcers! A.A tarcet is invicatcd to a Lattery comiander by its descristicn and eeaneral Location. In adcition,it may be tracked for two or thre. observations anc its predicted position for a convenient interval ahead located. This predicted position is relocated for the battery cy means of the pantograph attachment of the F’ plotting board,when provi- ded,and the relocated range and azimuth sent to the battery commander's station. The fire commander's instrument is set to the predicted azimuth and "now" called over the telephone as the target crosses the vertical wire. C.A.D. RSD. 7.Q.How may a fire commander concentrate the fire of two or more batteries of his command on a tarcet already under fire of one of them? A. By the commana,"sA:TEXY------ (or BATTERTIES------- and ------ ) TARGET vNDEX FIRE ,COMMENCE FIRING". 8.Q.Under what conditions is it not permissable to use this command? A.This method should not be folhowed if more than one fire command is in action,since a battery commander might mistake the tarcget.U.a.D.R.O55 9.Q."vhat is the ordinary method of indicating a &arget prescribed for the use of a battery commander? A.ithe battery commander having identified a target indicated to him from the fire commander's station by description,place in line,or otherwise,it must be indicated to and iflentified by the observers at B' and B" and the gun pointers. ‘the battery comuander,using the observer's line, commands JARSEL. Lhe observers reply B' and b} respectively. The battery commander adds a description of the target and at night gives the designation of the searchlight covering it,makes sure that it is correctly identified by the observers,designates the point for observation,and then commands 1RACK, C.A.D.K.540 10.Q.Do the methods of indicating and identifying targets differ in a battery of the intermediate armament (4.7,5,and 6 inch guns ) from that employed for the primary armament (cuns of 8 inches and larger caliber and 12 inch mortars ) ? A.No. 11.Q.Yhen the fire commander relocates the target for the battery commander's station, wha& action does the battery commander take? A.He transmits the azimuth to the guns,range and azimth to the plotter, and a description of the target to the observer. C.A.D.R.481. 12.Q.Under the above circumstances what do the gun pointers dot A.lthey set their sights to normal,3 on the deflection scale, and cause the gun to be laid at the azimth given. The battery commander or his assistant calls,"now" when the target crosses the vertical wire of the B.C.,instrument,. 57 The gun pointer calls "on target" or "lost". If the gun pointer fails to identify the target at the first trial,the operation is repeated with more detailed description. Identification may be confirmed in the same manner as for observers.C.A.D.R.485 13.Q.Under the above circumstances,what do the plotter and plotting detail dof / A.See Duties of Plotter #P Duties of Nod” finder heading,Indication and Identification of targets, Aagta G3 lo /lSe 14.Q.Under the above circumstances,what do the observers and readers do? A.the battery commander's observer sets his instrument to the predicted azimuth received from the fire commander. whe fire commander's observer calls,"NOW" when the target crosses the vertical wire of his instrument; this message is transmitted to the battery commander,who repeats, "NOW" to the observers, both observers naviny reported to the battery « commander,”"ON 1ARuE.",he designates the point of observation and commands ,"TRACK". C,.A.D.R.481 The readers set the observing instruments to the azimths received from their respective armsetters. 15.Q.What change is made when the vertical base system is to be used? A.None in method except that the description,azimth,and range are sent only to the station (K' or B") at which the D.P.F.is to be used. — 16.Q.What action is taken when,after the command,”'RACK",one or more stations do not appear to be on the proper target? A.If,after the command ‘RACK,the battery commander has reason to believe that there is a possibility of confusion of targets on account of the number in the field or other reason,he commands B' (or B") DESCRIBE, The B' (or B") observer,without ceasing to track,describes the target giving details in addition to those furnished him by the battery -.> commander in indicating it. When B' (or B") has confirmed the identifica- tion of the target to the satisfaction of the battery commander, the latter pepeats back "on target B''" (or B"),and then commands 8"(or B') DESCRIBE,until the identification is confirmed.C.Aa.D.R.483 17.Q.Is there any other method in general use? A.Yes. It is as follows: Suppose B" is on the wrong target. ihe battery commander commands}B' ,RELOCATE FOR SECONDARY. B' tracks by vertical base until 8' operator hears over the observers’ line that B” has identified the correct target and is sending data for horizontal base trasking. the plotter plots the target by vertical base data along the primary apm and causes No. 3,B" armsetter,to transmit the range and azimith of the point from B". 8" reader sets the instrument in azimth while 5" observer sets the instrument for the range indicated and identifies and reports,"ON 1ARsE:",as soon as practicable. J 18.Q.Is the last method prescribed in C.A.D.R.t | A.No. 19,Q.Which is the more rapid usually? A.the first. 20.Q.When is the second to bg usedi A.When the first method fails and when there are many targets of the same general appearance in the same part of the field. 21.Q.How may the battery commancer check the identification of the target? A.the battery commander may have the gun arm azimth called to him from the plotting room for checking with his observing instrument.C.A.D.R.484. 22.Q.Is this check of any value in a battery which has but two of the three stations,}.C.,B' and B"? In a battery which has but one of the three stations? A.It is a check in a battery having two stations only when the plotting has been by vertical base data from the station which is to be checked up. It is of no value in a battery having but one station except as a ‘check upon the travel correction made upon the deflection board. 23.Q.Should the azimuth mentioned in question 21 have any correction applied to it before it is sent? A,See question 23,Duties of No.l in Plotting Detail,page/9QO . 24.Q.Can either actual or corrected azimth be used,if it is understood which is sent? : A,See question 24,Duties of No.l in Plotting Detail,page /O/ . 25.Q.At what stage of the process does the battery commander indicate the target to the guns? A.Immediately after the observers have called,"ON ‘'ARsEI".See C.A.D.R.485. 26.Q.Is it necessary that the b.C.observer have his instrument set at an azimuth derived from the plotting board in order to indicate a target to the guns by azimuth? not A.It is necessary. He may set his instrument an arbitrary (discretionary) amount ahead of the target,alloving sufficient time for the transmission and setting of data. If the readin- for this setting be now transmitted to the cuns,the gun pointer and b.C.observer act as outlined under question 12. 27.Q.by vor and in what manner are targets indicated to the emergency station! Aslarcsets arc indicated to and identified by the emergency station in the same manncr,the range officer or No.7? using the speaking tube or megaphone as means of communication for t.i8 purpose.C.A.D.H.486 The"same manner"means the same as described above for other stations. ©8.Q.Point out on the diagram of fleet formations the follovins: (a) Line abreast \Mav.) Line (Mil.) (b) Line ahead (Nav.) (c) Line of sections in colum. (d) Indented line (e) Double line (f) Double column (g) Exact colum (Mil.) (h} Echelon-Zine of bearing 4 points. (i) Double echelon-Retreat (j) Double echelon-Chase Note:Frinter insert here diagram of fleet formation shown between pases 20 and 21,Coast Artillery War came. 29.Q.tshat direction are the ships supposed to be moving on the chart? A.Towards the top. 30.Q.What is the meaning of the expression "Line of bearing 4 points." A.See "Points" in Nautical and Naval Definitions in appendix G. 31.Q.How are ships in line designated? A.By numbering from the starboard ship toward the port ship. 32.Q.How are ships in column designated! A.By numbering from the head of the column, classifging ships for purposes 33.Q.What is the coast artillery methoa, of indication and identification of targets? A.The ship is dsecribed by a number of two figures,as "Class 12", pronounced "Class One Two",meaning that it has one funnel and two masts. Similarly a ship described as "Class 42",pronounced "Class Four Two",has four funnels and two masts. rhe first digit indicates the number od funnels and the second digit the number of masts. See sketches of the several classes. Note: Printer insert here illustrations from Page 21,Coast Artillery War Game, GL 34.Q.What searchlight beams are visible from_____._ and what is the size and location of the lights from which they come? A.Beam No. Size of Lirht Location Area covered, inches. (Printer should leave about 5 inches of space for addition of proper data by battery commander) 35.Q.What advantages arise from dividing the battle area into sub—areas and announcing this sub-area immediately after the word,™l’argoet"? A.the announcement of the subarea as the first part of the indication of the target serves to fix the attention of all observers and gun pointers in the proper yveneral direction. she general description which then follows is not forgotten or confused in a vain search from vessel to vessel for the one indicated. shis method also enables the plotting detail to prepare for tracking in the dseignated sub crea. the plotter and armsetters have time to note about what data is to be expected and to promptly report the failure of one station or the other to identify the proper target when{the error is sufficiently large to be evident, 36.Q.What are the names assigned to the sub-~areas of this battle commana: A.Name of Sub-area Extent. Bartlett's Reef Vicinity of Bartlett's HKeef Light Ship in Long Island Sound. Plum Island Southern half of Long Island Sound in battle areae the Race Vicinity of fhe Race. Constellation Rock Vicinity of Constellation Rock bouy. Fort Pond Bay From Constellation Rock area to Gardiner's Island° Block Island Sound Area beyond Constellation Rock. Montauk Point Area beyond Hort Pona Bay area and in direction of Montauk Point. Gardiner's bay Gardiner's Bay Plum Gut Vicinity of Plum cut. a Gf 37.Q.In describing the target in what order should the details be arranged? Why? A.(a) The general type of target as Monitor, Submarine,Destroyer, Cruiser, Scout, kattleship,!tramp steamer ,0il tank,#rigantine,etc. (b) If in a group of warships acting together,give the eerm which indicates the size of the group;Division,for 3 to 8 ships,Squadron for 6 to 10 ship (¢) she formation in which the ships are moving: Line abreast; Line ahead; Double colum. (d) Location of target in group:Ship No.4,or,Port Colum ,Ship No.2. (e) Direction ship is going:Coming in;or Going out. shis is not always nec- essary and should be omitted in the interest of brevity except when necdaqj, the purpose of this arrangement is to have the description reach the observer or gun pointer in the order in which he requires it for selecting the target from the whole number of vessels in view. 38.Q.Point out on the battle Chart where you would look and,on the diagram of fleet formations,the ship indicated by the following Commands: the instructor or examiner will add the necessary number of commands from the sype Commands given or will make up new commands following the same princi- ples, After each command the following question should be asked until each candidate? has caught the distinction: 39.Q.Is this a fire commander's or a battery commander's command? | TYPE COMMANDS FOR bAITERY COMMANDER l.Target-. 2.Constellation Rock~, 3.Monitor Division-.Line ahead-.Ship No.l (Observers report,"B',B",Hmergency,On Target" )-.4.Tragk-. L.Target-.2.Bartlett's Reef-.3.Tramp Steamer-.Class 12,Coming Im (Observers report, "B' Bp", Emergency,On Target")-.4.B' Vertical Kase track-. : 1.Target-.3.The Race-.3.Submarine Division Ship No.8 ( Observers report "B',B", Emergency,On farcet")-. 4.Vertical Base i'rack-. FOR FIRE COM ‘ANDER 1.Battery Bradford-. Target-. 2.Block Island Sound-. 3.Fall River Line-.Coming in- 4, Fire when in range-. 1. Battery Dimick-.Tarset-. 2, Gardiner's Bay-. 3. Oil Tank-. Class 13, Going out-. 4.Fire iwo Rounds—-. 5.Commence Firing-. 1.Battery Hagner=.Tarcet-.2.Plum Gut-.3.Submarine Division-.4.Ship No.3-. 5. Commence Firing-. 1.Battery Floyd-. ‘larget-.2.Gardiner’s Bay-.3.Gun Boat Division-.4.Fire at ships in order in colum-, 3.jninute intervals—. 5.Commence Firing-. 1.Battery Kelly-.2.Target in No.6-.3.Fire Iwo rounds~.4.Commence Firing~. 1.Battery Campell-.arget-.2.Fort Pond Bay-.3.Destroyer Division,Double Line-. Second Line-, Ship No.a. 4.Fire when at 7000 yards-. The formation Line Ahead can be frequently simlated at drill by a tug towins barges or tarsets. In such cases,the barges or the targets,are numbe-ed from head to rear thus; L.Target-. 2.Plum island-.3,Coal Barge Division-.Going out-.$hip No.l (Tug) or barge No.2 (Second barge )-.%.Emcrgency System-.5.track~. * a Target-.2.Bartlett's Reef-.3.Scully Line Division,Barge No.l-.4.B', Vertical Base-. 5.lrack-. _ 1.Tarcet-.2.Montauk Point-.3.ureene Division=.Target No.a=. 4, Track-. 1.Tarpet-.2.Plum Island~.3.S5and Dredse Division-.Dredge No.1-. 4. Track-. 40.Q."nat do tne observers do immediately after receiving one of the above commands! A.B‘ observer calls over the observer's line,"Fore mast","Funnel No.l" or other description of a narrow but distinct part of the target. 3B” observer calls back,"0.K." or "Can't see it" and addsdescription of a point he can see. When they have agreed upon an observing point, they begin to track. 41.Q.Why should the observers select the foremast or forward funnel(funnel No,1) of a ship coming in and the mast or funnel fartherest aft of a ship going out? ‘A.pecahse life boats,boat cranes,side turrets,signal flags,sails or other objects may hide points farther away from the stataons from the other base end stationg. .\.For the gunnery reasons for this selection,see Plotter IV,Elementary gunnery (a) Explanation of the several corrections to be applied to the observed range to obtain the corrected range, page /24. 42.Q.\ihat advantage arises from allowing observers to select their ow aimince point? A.The battery commander cannot be sure that the point he selects is clearly visible from both B' and B". Responsibility for agreeing promptly between themselves teaches the observers to appreciate the importance of selecting proper pointsfrom the standpoint of both of the reasons given above. 43.Q.Is this command of execution,"frack” essential? A.Ihere is a wide difference of opinion upon this point. We are habituated to a command of execution from its necessity in infantry drill. The argument of those who favor omitting it is that the conditions which require it on the drill ground do not hold in this case,that it lengthens the telephone message,that it delays the beginning of tracking since the preliminary part of the command conveys fully the will of the superior,and that it tends toward an iron bound,rigid system which cripples proper and well directed initiative without corresponding advantage e 44.Q.Are such departures from C.A.D.R. as are covered in questions 40 and 43 permissable? A.C.A.DR.3L6 states; The battery commander is encouraged to improvise devices and methous which in his opinion will simplify the fire control system or increase the efficiency of his command,and withthe approval of the district comnander is authorized to test such devices or methods at t@rget practice. When the result is favorable to the device or method, the test shall be made the subject of a detailed report,accompanied by drawings and models of any device used. Note: The compilers desire to avoid the appearance of advocating sonething new simply because it is new. In the spirit of progress which the C.A.D.R.secks to foster,the successful metiods originated by other officers are placed before battery commanders for consideration or. their own merit. PLOTTER: II Fire Control. (c) Duties of Plotter.- 1.Q. A. 6.Q. A. 3.Q. 5 Q. . The What is the definition of a plotter?- A member of the fire-control section in charge of the plotting.(C.A.D.R.183) For The what specific duties is the plotter responsible?- plotter is responsible for the adjustment and operation of the plotting board.(C.A.D.R.332) Who is in charge of the Fire Control Section?- Plotting Detachment? The Plotting Board Detail?(C.A.D.R. 283 and 285). senior noncommissioned officer of each section,detachment , and detail is its chief. Each chief commands his own subdivision whenever it acts separately and is responsible for its drill,its efficienoy,and the condition of the materiel to which it is assigned.(C.A.D.R.285). The How many men are required to be kept trained for each positicn in the fire-control section?- Company commanders must keep two men trained for each position for which they furnish details in the manning party of the battle and fire commanders' stations and two men for each position in the fire-control section of the battery.(C.A. D.R.389). When the target is indicated by a description of its general locality on the water or with reference to a searchlight | beam,appearance,and direction of motion,what action does the plotter take wéthout delay? When does he begin to plot? The plotter locates the approximate position of the target on _ the water and causes the primary and secondary arms to be moved to this vicinity in order that he may notify the battery commander in case either station is too near its limiting azimuth to warrant ite tracking and in order that he may more quickly detect a failure to identify target by either station. He begins to plot as soon as readings are received from primary and secondary. When the target is indicated by its azimuth and range,what action does the plotter immediately take? How must the range correction scale set? Why? He locates the position of the target on the plotting board by means of the gun arm. The range correction scale must be at normal since the range given by the fire commander :s always the actual range from the battery commander's etation.(C.A.D.R.481 and 554), Where can the plotter telephome by means of his head set?- To the range recorders in each emplacement, be 8. Q. A. 10. ll. Q. 13. Q. 14. except that in some batteries where the plotting room is not within speaking distance of the battery commander's station,the B.C.station is also cut in on the plotter's line to the guns. What is the base line switch box and who operates it? In all batteries equipped with a horizontal base,the base line switch box (See Fig. ) is installed in the plotting room and is operated by the range officer,or by the plotter in his absence. It contains two double pole,double throw . switches. B'armsetter(No.3) is connected to the central posts of the upper switch. B"armsetter(No.3) is connected to the central posts of the lower switch. B'reader is connected to the right: poles of the upper switch and the left poles of the lower switch. B"reader is connected to the left poles of the upper switch and to the right poles of the lower switch. What is the purpose of this base line switch box? To put both armsetters (No.8 and 3) in communication with the reader at the station indicated when "B'(or B") VERTICAL BASE" is ordered.(C.A.D.R.500). How should the switches be set? - For horizontal base system,both switches to right. For B',vertical base,upper switch to right,lower to left. For B",vertical base,upver switch to left,lower to right. Should both switches ever be set to the left at the same time? Why? Because No.2 will be connected to B"reader and No.3 to B' reader. No. Will No.3 or No.3 ever find themselves in commumication with anyone else besides the B' and B®" readers? What is the purpose of these connections? the B.C.station there is another set of switches which allow either No.8 or No.3 to be connected to B!' and B" observers at the same time when the line to their own reader is out of order. Connection can be made so as to bring the battery commander,voth observers,and both armsetters on to the line at once. In What precaution should be taken by armsetters before setting data they hear? They should learn from the party talking who he is in order to guard against setting erroneous data,as in the case when both switches in the base line switch box are thrown to the left. Horizontal Base system Is there any advantage in bringing the targ against one arn in preference to the other before sliding it along to the intersection? Which arm and why? 15.Q. > 16 .Q. > 17 .Q. 7 13.Q. A. 19.Q. 20.Q. = 61.Q. = 83 .Q. _ 23.Q. > GI What does ©C.A.D.R.prescribe? It depends somewhat upon the location of the target on the board the position assumed by the plotter,and the shadow of the targ. The secondary arm being the higher of the two arms affords a somewhat better guide for the targ. C.A.D.R. 490 prescribes the secondary arm. What is the plotter's next step as prescribed in C.A.D.R.? To bring the gun arm to the targ,noting that the range correction scale is at 2000Cantil a range correction is made by the range board operator after the second rahge has been read). What step follows the bringing up of the gun arm to the targ? To read the range in a distinct vcice into the transmitter of his head set. To whom does this range go? To the range recorder at each emplacement (C.A.D.R.8234) who operates the time-range board,to the B.C.station by the gun telephone line when plotting room and B.C.station are separated,and by voice when they are not separated,and to the range board operator and deflection board by voice. Is the first range actual range or corrected range. Actual range. In reading actual ranges into the transmitter,how does the plotter indicate that they are not yet corrected and are therefore not to be use for firing? By calling out "Actual Range" before adding the figures of the range reading. : Show how to read the following ranges:5380,6300 ,5000 ,5050. Five,three,eight,zero;Six three hundred;Five thousand;Five, zero,five,zero. What is the object of this method? To enable the plotter to pronounce each word in a clear,strong tone distinot from the other words,to make the message brief,to avoid the confusion to the range recorder from receiving a series of zeros,aygd to indicate by the différent manner of framing the message the difference in character of the four typical ranges shown above. What step follows the reading of the range? Plotting the position of the target on the paper placed on the plotting board for that purpose, (°.A.D.R.490). What two methods of plotting the target are used:? Plotting with and without the targ? Both require for accurate work a hard pencil (3H to 6H) carefully sharpened and with the wood trimmed back about an inch and a half from the point in order that the point of the pencil may be accurately placed under the intersection. Which method is best appears to be a matter of opinion. Without the tare the pencil must be held so that the side of the sharpe:ed part of the pencil next to the station arms is vertical. Perhavs the best method is to sharpen the pencil in-such a manner as to expose about 5/16 inch of lead so that only the lead touches the secondary arm thus bringing the vlotted point within one half of the thickness of the lead from the inter-section. 24.9.When a point falls materially to one side of the probable track as established by prolonging that obtained by the last few nlotted positions,or when the interval isa too small or too great what action must the plotter take. A.He must decide instantly whether the variation is a reasonable one due to the target starting to turn,to increasing speed, or to stopping. If it is reasonable he calls out the cause before announcing the range as,"Target Turning","Target Stopping". The increases in speed are usually too slow to make the announcement of much value to the persons receiving his message. When the change is an unreasonable one he calls, "Reading Lost"and investigates the cause without interrupting the tracking. 25.Q.When the track approaches the inner or cuter limits of the board, what action does the vlotter take? A.He calls to the 8.C.station about two readings before the limit is reached,"Inner Range Limit" ,"Quter Range Limit"as the situation requires. 86.Q.When the track approaches either limiting azimuth for horizontal base plotting,what action does the plotter take? A.He calls to the 8.C.station about two readings before the limiting azimuth is reached,"Secondary Azimuth Limit"or "Primary Azimuth Limit" as the situation requires. 27.Q.What purpose does this warning serve? A.It enables the B.C.to determine at once whether he can continue tracking by ordering "B', (or B") Vertical Base, Track" for some time longer or whether the target is going under the gun arm azimuth circle or off the board. When “Inner Range Limit" or "Outer Range Limit" is reached the target can no longer be tracked and "Cease Tracking" or Change Target" will follow. 88.Q.What are the usual factors in fixing these limits for horizontal base plotting? -_- 7/ A,The following conditions are the ones which are most frequently found to be the causes which fix these limiting azimuths: Some obstruction in the field of view external to the observing station as a hill,forest,buildings or other object. Some feature of construction of the observing station itself as the side of a window frame or a nost. Secondary arm or coupler hitting index box on auxiliary arm as the two arms approach each other near the right or left hand end of the board. 29.Q.What lines should be nermancnt+ly marked on the board? A.The azimuth limit for horizontal tracking for each station and the azimuth limit for vertical base tracking for each station. 30.Q.Where should these lines vce marked? A.Along the graduated edge of the primary,the secondary arms, and the gun arm when set to the limiting azimuths for their respective stations. 31.Q.What other lines may it be advisable to have permanently marked upon the board and why? A.Azimuth lines from each station to the several salvo points and to light Houses,datum points or other fixed points of reference. This enables these fixed points to be quickly located and the time at which firing should begin to be determined when the command,"Fire on salvo point No.1," is received. The location of other fixed points assists in checking up emergency range finding. WS II FIRE CONTROL SYSTE7. (c) Duties of “No.l (Assistant Plotter! 1.Q. What are the dutieg of No.l upon arriving at the plotting room? A. To prerare for service and adjust the wind component indicator the range correction scale,the azimuth correction accle, ul arn azimuth scale pointer,and tally dials. to 2.9. How socn should he begin to crerave the Wing component inuicator 4.As soon as the meteorological message is received,which snoula be in the first five minutes of the drill period after arrival at the battery. 3.Q.Wnat data in the meteorological message is used on the wind component indicator? A.Azimuth and velocity of t.ind. 4.Q.”here does the meteorological messaze criginate?Trece tie tele honic channels thru which it comes. A.It originates in the meteorological station and is telephoned tc the fire command stations which stations relay i* to each of their respective 2.C.stations. Rach B.C.station then relays the message to it3 own plotting room. See C.A.D.R.617. 2eQ.How m ny copcortunities are there for its being misunderstood? A,It may be misunderstood by the F!' telephone operator who receive: it,by the F' televhone operator who receives it by voice anc Bends it to B.C.,dy the #.C. telephone operator on the F! line and by No.l when he hears this last operator call it out or four opportunities all told. When the plotting room is sevarated from B.C,,the 3.C.operator on the plotting rooni line and the plotter may also misunderstand it,making a total or six times. 6.Q.How many oprortunities are there for the meteorological mes-caye beang inwroverly transmitted. A,By the neteorolopical observer,in relaying by voice in F!',in transmitting to 8.C.,in relaying by voice in 8.C.,or a total of four times. When the nlotting room is senarated fro. R.C., tne P.C.overator on the plotting room line and the plotter may also transmit it improperly,nahkiry a total of six times. 7.Q.What should No.1 deo when he receives this iessage? A."“e shoula record it in order that it may be checked with the message origirally sert from the meteorological sataticn. 8.Q.Is this data required for any target practice record? Which? A.Yes. It is required on Form No.821l-Reoord for Plotting Room. 9.Q.How frequently should this data be received? A.The velocity and azimuth of wind should be recorded at least every twenty minutes,and oftener if necessary;any sudden change, either in direction or velocity,of any considerable magnitude is reported at once to the fire commanders. When the atmosphere reference number changes by more than 1 per cent,the barometer and thermometer readings and the new atmosphere reference are reported to the fire commanders. (C.A.D.R.618). 10.Q.What action must be taken when this message is not promptly received? A.The plotter's attention must be called to it so that he may promptly report the delay to the B.C. 11.Q.From what source does No.1 obtain the azimuth of the target? A.From the gun arm azimuth circle. 18.Q.How closely is it necessary to read azimuth of target for this purpose? A,.To the nearest degree. 13.Q.Should he set the wind component indicator to the actual azimuth or the corrected azimuth of the gun arm. A.The corrected azimuth,which is the one that is read from the gun arm azimuth circle when any agimuth correction is made,as in Case III,is the proper one but the difference is immaterial. 14.Q.How often does No.1 change the setting of the wind component indicator? A.He sets the target arm to the azimuth of the gun arm after each setting of the latter.(C.A.D.R.491). 15.Q.Who uses the range comvonent? A.No.4,the range-correction computer. 16.Q.Who uses the deflection component? A.No.5,the deflection computer. 17.Q.Does No.l call off the component or do these men read it for themselves? ay a’. A.No.4 and No.5 read their own values themselves. No.1 does not call them off. See par.7,0.P.1794-1908. 18.Q.Describe and illustrate the method of obtaining the wind components. A. Set the pointer to the wind velocity,turn the azimuth ring until the azimuth of the wind is under the triangular index and keep the target arm set to the approximate azimuth of the target as indicated by the gun arm on the plotting board. Should the wind change,make the necessary changes in velocity and azimuth of wind. See C.A.D.R.828. INDICATIO™ AND IDENTIFICATION OF TARGETS. .19.Q.When a new.target has been indicated by range and azimuth of a predicted point from B.C.what are the duties of No.l. A.To set the gun arm to the azimuth of the predicted point by means of the gun arm azimuth circle,the azimuth correction scale having been first set at normal. He must also note that the range correction scale is set at normal. See C.A.D.R.481. 20.Q.Does No.l ever have occasion to read the gun arm azimuth except when the battery is firing under Case III? A.Yes. The battery commander may have the gun arm azimuth called to him from the plotting room for checking with his observing instrument.(C.A.D.R.484). 81.Q.Who listens to this call and what does he do with it? A.B.C.observer when B.C.station is immediately above plotting room. When stations are separated the plotter telephones the azimuth to B.C. The observer sets his instrument to this azimuth. If the target comes on to his vertical wire at the proper time it shows that the observations from stations furnishing data and the plotting are correct. 23.Q.When should it be sent? A.Only when ordered by B.C.and then as nromptly as it can be determined. 25.Q.Should this azimuth have any correction applied before it is sent? . A.B.C.observer can utilize the azimuth of the predicted point best,i.e.the azimuth of the plotted point corrected for travel during prediction interval only. Corrections for wind and drift should not be made. s - e ' e - . "y : - °° ‘ nN o ‘ u . ° So! The above is the method followed in mortar batteries before firing each salvo.See C.A.D.R.511. When the purpose is merely to ascertain whether or not the proper target is being tracked a less exact azimuth reading is usually sufficient. 84.9.Can either actual or corrected azimuth be used,if it is understood which is sent? A.Yes. If actual azimuth of plotted point is sent the B.C.observer can cease tracking on the sounding of the bell on which it is desired to check. If corrected azimutn is sent it would be best to correct for travel during prediction interval only. HORIZONTAL BASE SYSTEM. CASE I OR II. 25.Q.Name the operations performed by No.1 in the order of their performance ,after tmacking begins. A.Note the setting of the range correction and azimuth correction scales,calling the plotter's attention to settings if he believes them to be improper. Set the velocity of wind on wind component indicator. Set the azimuth of wind on wind component indicator. Call the reading of tally dials(This operation is omitted on first observation) Set tally dials to normal. Note azimuth of tarcet. Call,"Set": Set azimuth of target on wind compvonent indicator. £6.Q.In what position must the gun arm be when he reads and sets the tally dials? Why? A.The gun arm must be set against the targ held at the interseact- ion of primary and secondary arms. If this is not done,the readings will be of no value since they refer only to the chance position of the gun arm when it is thrown aside. 27.Q.Why should he wait for the plotter to announce the range tefore calling off angular travel? A.Because both the range correction and deflection computers require the range,the latter requiring range earlier than he does angular tarvel. Failure to do this will be confusing eepecially if both range and travel are called at the same me. 68.9."hy should he call off angular travel of target as soon as the plotter announces the range? FOZ . .: A.To reduce the time required for orer ation of tne | Geflection b@ard ana te lessen the tine the nlotter 1 a required to held the gun arm in pition. 2° .0.8hy shiculd the assistant nlotter call "Set" as scon as he has his tally dials reset? T3 this nreacrined? "s A.To free the nlotter from the necessity of observing the dials before casting the gun arm asice for the next nlotting. 3C.9."hat is the normal? A.Tne normal on casree tally dial is 15 and on the tally subidial is zero. 31.Q.What coes"the normal" mean? A."The normal" in this sense means a standard condi ts ence. ™ this cise,a sondition of no angular . Por tue use of 841s tearm with the gense oF being rer= ular te something else,see definition of the normal of the plotting coard under TIT Fire centre] arnaratus, race / f and the aefinition cof the anyle of incidence C,A00.T.2 and "ig. ,Paze JZ3 . 32.9."hy i3 it used? an > a Ho 63 4 oO p— A.To avoid the use cf vrlus and minus or right and left in describing the direction of travel. It has teen found tat even with hishly trained nersonnel,the correction will nos infrequent;y be wide in the wrons direction. The use of some arcitrary number, like 15,cives but one prssible setting for the ficures called out.1S5 was chssen because it was larce anouch to insure that no case of negative travel would arise. 33.9."“nat do the tally dials read? A.The tally dial sarked 15 at tie normal reads whole degrees co? movement of the cun arm. "ne tally suo-dial reads hundredtrsa of aegreea. Test dy means of the cun arm azimuth dircle. 34.9.What precaution must be exercised in readins the decimal rart? A.TO read the hundredta cf degrees on the tally sud-cial and not cn the gun arm azimath gub-dial insice. iy ‘ ee. ‘ - ® ~ . —_—-———_ 35.Q.U40ow may No.l guard hinself against error in tally dial reading and what should he do when he aectects an error? A.He should accustom himself to noting the rezularity of his readings. If they are the same or gradually increasing or decreasing his readings are correct. A single irregular orc indicates an error in observation,in azimuth readings,in plotting,or in tally dial setting. The armsetters will detect the first two,the plotter the first and third. No.l must detect the fourth and call,"Readirg Lost" ,except when the target is turning. When the targ3t is turning the first irrezular reading will be followed by others still more irregular in the same direction. The turning of the target will usually be noted by observers,armsetters or plotters vefore No.l can notice it. 36.9.Which way is a target travelling when tally dials read 17.25: A.¥rom left to right. 57.Q.Can you tell from the above ho. faat the target is travelli:.7 Wuas else must you know to do so? A.No,If whe speed of the target was to be computed it would be nesessary to take its range irto account. This is done v7 vLe nechanism of the deflection board but even this coari vy its system of graduation gives the result in degrees and hundredctns instead of vards ner second cr miles rer nour. : oc .Q.Why measure tiie component of travel at right angles to the gun arm in degrees instead of yards? A,Recause the gun nointer observes the change of position of the target as a change in angie from his position. He could not use tne travel if it were given to him in wiles ver nour or vards ner second. 69.9.Who listens for your call of the travel reading? A.,No.5,the deflection computer. = 4C.9.¥or whose ultimate use at the gun are you obtaining this data? A.¥or the gun pointer. 41.Q.Who is charged with settinz the range correction scale? A.No.4,the range correction computer.See C.A.D.n.498, 42.Q.Who is chargea with setting the azimuth correction scale? A.No.5,the deflection comsuter.See C.A.D.N. 494, & SOY 43.Q.Thould “o.l ever change the setting of either of these scales? “,Only when directed to do 30 by the Plotter CASE III. 44. 2. Does No.l's duties change when Case ITI is ordered? In what ay! 7 ; A.Yes. He calls off the corrected azimuth of the target. 45.Q."hat ia the new crdaer in which he vnerforms his duties? A.Tnere is no change excent to announce the corrected azimuth of the tarvet in degrees and hundredths where under Case I or Case II “he Would have read to himself the azimuth to the nearest gegree only. 46 .0..Mhat additional correction wust he made to the gun arm now? “ho makes it? A.’ he azimuth correction must be set on the aginuth correction scale by Mo.5,the deflection convnuter. 47.9.“hy is this correction made? A.It is made so that,after correcting for drift of the projectile and wind,the gun will be so nointed that the nrojectile will be directed ahead of the tarset bv the amount necessary to arrive at the set forward point at the sine instant that the target arrives. 48.9."here is the azimuth of the sun arm read? A.The whole degrees ar? read at the pointer in the window over the gun arm azimuth Pare le and the hundredths of degrees on the oun arm azinuth sub-dial. 45.9."hat rrecaution must be exercised in reading the decimal part? A.To read the hundredths of aearees on the gun arm azinutn sud- Gial and not on the tally subd-dial just oitside cf it. If the order of operations given in Questior, 35 is followed the tally sud-dial will now vce reading zero a..a this mistaxe will not be made. ap C.A.D.:.491L prescribe that "o.1 shall call off the rected azimuth at every setting of tne gun excent the st two. 5C XD ouDy GO O cor fir A.%ecause it takes two settines to obtain a travel reading. ‘fter the second rexding the aeflection commuter must have time to cempute and set the azimuth correction. S05 51.9.Whe listens to this call ana What does he do witn tne uate? A.Ths plotter. Ne transmit i* to the deflecticn recoruer who reeordgs it as he would deflescticn fer Case I cr Case JTI.See C.A.D.R. 7684, 3 >.9."n0 uses corrected azinuth ard where? 1 A, Tne gun nointer uses it to set the gun in azimuth by means of the azimuth oointer. 93.9.Under what conditicns is Case III used’ A.“Wnen fog or other conditions obscure the target or after the Sight has become unserviceable. See C.A.D.4.5338. AUXTLIARY HORIZONTAL BAS SVETE?. 94.Q.D0 the duties of No.1 change when "RB! (or BR") AUXILIARY BASE TRACK," is ordered. A.No. VERTICAL BASE SVYSTEE, 55.Q.Ne the duties cf No.l change wher,"R' (or BR") VERTICAL PASE, TRACK," is ordered. A.No. EMP RCENOV SVOTHIY, ul oO .Y.Do the duties of No.1 change when, "R'URAGENCY SYSTEM, TRACH, ® ordered. + cn A.No. SERVICE TARCET PRACTICE, o7.9.Do the duties of No.1 change from those in drill or acticn Gurirn.g service target practice. A.No,excert as stated in next answer. 98.Q.Are any data observed by No.1 required for service target practice rerorts? What data are required and cn what rerorts? A.Yes. The tide,atmosthere,range and deflecticn components cf wind,setting of range correction scale and angular travel cf target at time of firing each trial and record shot are required for form 651,hecord for eyo e Ane oom. In sone batteries it is customary when nc range officer is present, bo ,pa7e mo.l note all of this data’ unaer direction of the 76 PLO. TER II FIRE COMLROL SYSiEM. (a) Detail:d knowledge of system employed at the battery. Note: whis is also subject II ajof the examination for Observer. Subject VII (a) for Gun Commander and Gun Pointer requires a "general" instead of a "detailed" knowledge of that in use at the battery. Examining officers should therefore require only a general knowledge of the following from candidates for the positions of gun com-ander and gun pointer, 1.Q.What two types of fire control installation are there in service? A.Provisional systcm and standard system. 2.Q.When is each installed? A.The provisional system is installed for all the armament to which personnel is assigned at all posts in the service. .the standara system is installed,coast defense by coast defense,for the entire completed armament,whether in commission or not,as funds becuzxc available, utilizing such materiel of the provisional systems as is suitable, 3.Q.“hich system is at present in use in this coast defense? A.she - - - systen. 4.Q.Is the standard system the same in each place where it has been installedfivhy? No. Because fire control materiel is subject to constant change and improvement; so also is the method of installing it and to a limited extent the method of using it. Moreover,each installation is dependent upon local conditions of such varied character as to modify not only the scheme of installation but also the methods of its use. 5.Q.What purpose does the adoption of a type installation serve? A.A particular installation can not be well adapted as a permanent type; but assuming certain general conditions as to the site and location of stations, there may be formlated from time to time a type installation which will show the approved material and the general features of the scheme of installation believed to be best adapted to the assumed conditions. Such a type installation is that given below. 6.Q.Where does this type installation assume the battery commander's station and the plotting toom are located? A.B.C.station at the battery and plotting room adjacent to b.C.station. 77 7.Q How many stations does the type installation provide for a gun battery of the primary armament! A.Two observing stations({which may be used together in the horizontal base system or individually in the vertical base system) a b.€.station,and an emergency station. 8.Q.What new feature does this type provide for batteries of the intermediate and secondary armament! A.A separate rance finding system. 9,.Q.Explain the terms,"primary armament"Jintermediate armament" ana "secondary armament"? A.Primary armament.--vuns of 8 inch caliber and upward and 12 inch mortars. Intermediate armament.--Guns of 6 inch,5 inch,and 4.7 inch calibers. Secondary armament.--Guns of 4 inch and 3 inch caliber. 10.Q.What equipment does a battery of the intermediate armament receive? A.It may be similar to either that for a battery of the primary armament or that for a battery of the secondary armament,depending upon the location of the battery,its field of fire,anda the probable objective of its fire, Note; Questions ll to 14 inclusive concern candidates for observer only. 11.Q.hat is the equipment of a pattle Commander's Stationt A(Printer: Copy table I from C.A.M.No.4-09.) 12.Q.In what way does the equipment of the local battle commander's station differ from the above? A.(Printer leave 2 inci space for addition of answer.) 13.Q.what is the equipment of a Fire Commander's Station? A.(Printer: Copy rable II from C.A.?'.No.4-09.) 14.Q.In vhat way does the equipment of F’--station ciffer from the above? A(Printer leave two inch space ) Hote: -Candicates shoulo be requirec to stuay either questions lo to 24 inclusive or 25 to 30 inclusive depencinc upon the charactcr of installation at their respective catteries. L5.Q.hat is the equppnent of a b.C.station of the primary armanent? A.(Printer: Copy sable III from C.A...No.4-09), 16.Q.In “hat way does the equipment of a B.C.station of the primary armanent n differ fron the above? A.( Printer leave tvo inch space for acdition of answer.) 18 L7oqgeuhat ics the cquppment of a Plotting Room? A.( Printer: Copy Table IV from C.a."..No.4-09.) L8.Q.In vhat way does the ecui-ment ofthe plottine rocm differ from the alove. ae(Printer leave two inch space for adcition of answer). L9.Q.hat is the equipment of an Observing Station? Ae(Printer:Copy sacle V from C,A."'.M!0.4-09.) 20.Q.In what way does the equipment of theobservin: stationsdiffer from the above? A.( Printer leave tw inch space for addition of answer.) 24.Q."hat is the equipment of an Emplacement? a.e(Printer: Copy rable VI from C.a4.°'.No.4-09.) 22eQ.in what way does the equipment o8 theemplaccmenisdiffer from the above! Ae(Printer leave two inch space for adcition of ansver.) 23.Q."hat is the equipment of an Emergency Station? A.(Printer: Copy sable VII from C.A.M.No.4-09.) 24.Q.In what way does the equinment of sheemercsency station differ from the above? A.(Printer leave two inch space for addition of answer.) 25.Q.hat is the equipment for B.C.station for a battery of the secondary armament? A.Artillery sulletin No.94,April 17,1913 prescribes the following for rapid fire batteries: l. pattery Commander's Station: Self-contained rance finder. Telephone (head set) to range observers. telephone (head set) to spotting station and Fire C Commander. Deflection Board. Display Board. Range Board. Gelescope (3") Wield Glasses. Stop Watch. Vid 26.Q.2n what way does the equipment of the B.C.station at Bat tory------- aif fer frsom this? ae \Printer leuve about 2 inch space for addition of answer) 27. .QWhat is the esuipment for the Gun Platform of a battery of the secondary, armament? A. Gun Flatform: telephone to 8.C.Station. Signal bell Stop watch e 28.Q.In what way docs the equipment of the Gun Platform at Batiery----- differ fron this? A.( Printer lcave about 2 inch space for addition of answer.) 29.Q.\hat is the equipment for the Spotting Station of a battery of the secondary armament? A.Spottin= Station: telephone to 8.C.Station,. 30.Q.In vhat way does the equipment of the spottins station at Batterv------ differ fron this? A.( Printer leave about 2 inch s ace for addition of answer.) 31.Q.How many parts are there to a triancle? What are their names? A,Six. Three angles and threc sides. 32,Q.How many parts must you know in order to construct the triangle? A.any three part,except the three anrcles. 33.Q.\hy is this exception made in the case of the threc angles? A,see Fis, pymarked, "PRINCIPLE Ox HORIZCNiasl BaSE SySvEM, Note that i~ the nest of triangles on the left that all of them have the same ancles as triansle PB"B' and that many more could be similarly drzevn. 34.Q.What conclusion can you draw when you know any other combination of three pars? any tvo sides and one angle, 4.aS 800nN as any one side and two angles,or all three sides are knom, there can be but one triangle which will have these three parts. To those who have had geometry this will be a familiar principle which will be recognized as cusy of proof. To those who have not,a little experimentation with a pencil and piece of paper on which to make the angles ana matches broken to aifferent lengths to represent sides will be reassuring. By constructing the triangle,you discover the principle of both horizontal base anu vertical base s}$stem,. SO Note: In the sketch the three parallel dash and dot lines,marked 5S, represent meridian lines,i.e.enorth and south lines thru each of the two stations B',and B", and the directins point of ‘he battery,D.point. 35.Q."ny are ghe angles 1,1,2,3,and 6 in the sketch all measured in a clock- wise direction from the southern end of the meridian lines to the other boundins line of each angle? A. Kepeat the definition of azimth. What is the azimth of a point direétly soutt. of a station? Note: It is well to remember that in civilian practice it is customary to take north as zero instead of south. 36.Q.Point out the triangle involved in horizontal base system anu nane its pirts! A.ihe triangle is the triancle s5' B" P; its sides are the tase line 5’ B", and the ranges of the point P from p' and from b"s its angles are: (a) she azimith anrle 2,of the observer's line of sicht fron B' \represented on the plétting board by the gracuated edge of the primary arm) minus the azimuth,an,le 1l,of tne pase line ecuuls angle 4,the angle included between the base line,b' B",and the observer's line of sicht fre: B' upon the point P. (b) ‘the sum of the back azirnuth of the base line, i1.eo.the azimuth of B' from B",plus (for the particular case shown) 300°,which is represented also by the figure 1 in the sketch,minus te aziruth vancle 3,of the observer's line of sight from B" (represented on the plotting tourd by the graduated edge of the secondary arm) equals angle 5,the anrle include? between the tase line,B' b",and the observer's line of sight from b" upon the point P. Note: Cnc of the most complicated situstions which can occur has >e2n purposely ESLuned in the case of the angle 5 in order to bring out the cure with which accle 5S cen be found by adcing 360° to the back azimith o° the base linc in orcer *e obtain the ancle 1 show around the secondary staticr, pb". Tre sexe value for this angle l can be obtained by addin~ lec to the value of angle 1 shom arou:.d B', Uncer more simple conditions,the method would be tho same as uncer (a) above,i.ee.to subtract the azimutn of the base line,angle 4 around B’ frer the uziruth cf the line B" P,All depen’s upon the relatici. of the reridian lines to the sides of tne triuncle,. (c) ttc anple B' PRB’, 37.Q.Which of these six parts can we call the thre. tmoin parts after we have made use of the data obtained from the observers? relhe length of the base line and its Spach gre, kne TE lenpslugs tre v1 tne ne wit Q Lt first known part. By proper wahtree ee Sat hase at utits reed at 6' and pb” on the target P,we obtain the other ‘tro homn pa. arty ,tre ancles 4 and 5 adjacent to the base line. 38.Q. hich of the six parts cre ‘he three unknowmsi A.she sides B' P and B" P andthe enel: B' PB", 39.Q.Hovw can they be determined? ~ A.shey could be computed by te principles of geometry ana trigonometry but,even for a person familiar with these processes,this method is long and laborious. By reducins the actual layout on the ground and over the water to 1 of its size and representing tie different 7 _ 10800 parts vith suitable metal pieces,we have the device knot as the plotting -voard,where one inch on the plottinc board in any directior represents 300 yurds in the same direction on the surface of the earth, by making the arms representing the observer's lines of si,ht movacle and by adding suitable azinuth and rang: scales we can find automatically within a few seconds the unknown parts .hich we wish to know. The parts are the lencth of the sidcs p' P and Bb" P of the ranges of the tarcet from B' and B". We do not need to find the size of the angle at P. ” 40.Q.How do we learn the range by which to set the ¢euns before firing? A.By locatine the pun arm center,markecd by a small hole in the top of azimuth correction box cover,over the point on the plotting board which represents the directing point of the pbattory. Ihen bys ea the gun arm up to the point P on the plottin= Ao rh we can read, o the target,P,from D.Point and from the gun arm azirmuth scale,the azimuth of the target P from the directing point,D Point. are applied? A.It is not. The corrections which mst be applied are shown below: No. Correction By whom applied. 1 For travel of target until next bell Plotter 2 For travel of tarcet luring time of flight " 3 For tide Range board computer 5 For atmospheric conditions " " " fo For abnormal inizzle velocity " " " q For direction and intensit:; of wind. " " " 8 For wi. differences Range setter 9 Kor time elapsed from last !ell until the instant of discharce. " . 19 Arbitrary correction from observi:.tion of splashes Battery commander. 4 Adjustment of center of impact Range board corputer,. For the detuils of the method of making these corrections,sc* fan comanert and Gun Pointer,V, Service of the Piece (a) Duties of Range Setter, page wit Plotter,IV,Elementary gunnery,\a) explahation of the several corrections to be applied to the observed rance to obtain the corrected range, page /22. 5/ ETT O 41.Q. Is this exactly the range which should be set on each gun! What corrections 3 52 VERTICaL BAST SYS UT, 42.Q.How many stations and what kind of equipment are required for this system? A.One station equipped vith a cepression position finder and the usual accessories. 43.Q.\shere is the base line of this system? Point out its up. ° sud? A.See Tig. »ymarked PRINCIPLE OF VER1ICAL BAS:: SYSTEM. the base linc is the heirht of the telescope trunnions,H.I.(meanine heicht of instrmwunent) above mean low water,M.L.W.,correctéd for tide,T,and for curvature of earth and normal refraction,C.C. In ordcr not to complicate this sketch, the correction for curvature and normal refraction is shown as a correct- ion for curvature only. For the cor: ction for normal refraction and discussion of its conbination with correction for curvature,see Cbserver, III Fire Control Apparatus, questions to inclusive, pace ° the upver end of the base lisie is at the telescope trunnions. 44.Q.Point put the triaigle involved in the vertical buse systc. paris? 12.2 And name its A.The trianzle is B' R PB; its sides are thc base line B' R,the rance of the . e fn 2 ? oo tarcet R P and the line of sizht B Ps; its ansles are the richt ancle at R,the angle RP B ' af the tarcet,which by the principles of seonetry is equal to the depression anglc,and the anvle A at 3' complemer.t of the depression aacle (the ancle which it acd to the depression angle to make the sum equal 90°). WLC is the is necessary to 45.Q.Which of these six parts can we call the three know parts after ve have 4 nade use of tie tide messace and +.c depression ancle? AeThe le.rth of the vertical base, 'R, the ancle Rilwhich does not have to te e@ measure: becaus it is alwa:;s aricht anelejjnd the ancle a. 46.Q.\hich of ths six parts are the unknowns and how many of these do we need to determine? ad A.Ih: rance of the tarcet,R P,the side B'P and “he ancle RP B' at “ho tarec ty the latcsr is practically . known since,ignorince r: fraction,it is ecual to. the depression ancle. The only unknoin we need to deturinine is the ranre of the tarcet,R P. 47.Q.How can this be determined? A,It coul? be computed by the principles of seometry and trigonometry but this metuod is too loms and laborious. To accomplish this authomatically it tne telescope in is arranced in the instru «xt so that the movemert of eo depressioi moves a point? gun arm respectively,to the azirut called and then plottinc the point,P,at che rance calle, wn ™e process Of obtain nt the ra:ce from the dircetin, point is the sume ac is described undcr question 40 above. 490.Q.Is this cxactly the rane which should be set on eac cunt? What correciicus are apnlie:? A.It is not. the corrections which must be applied are tho saac as with the “orizontal base sysven., sce question 41 above. aAUATULARY Bast oYSiTt. 50.genhnat statio:s are used for-this system? Does this system usc the horizontal or tec vertical buse system? A.The P.C.Station is usec as the pr’mar; station anc cither B" or B' as the secondary station.See C.A.D.R.499. For detuils of she methocs of plottine sec Plottc.,II Fire Control Systen, (a) Duties of No.l and No.2 (arusetters) ,questions 13 to 16 inclusive, * pare ° this system uses horizontal base, ae EhERGOINCY SYouuit, §1.Q.What stations are used for the emergency system? Does this system use horizontal or vertical base? A.The emergency; stations are used for rance and the s.C.instrument for aaimcth until the latter becomes unservicable, ‘thereafter the azimuth is sent from the azimuth instrunexnt transferred to or permanently at the emergency station. Azimuth can be also be read from the Barr and Stroud self contained base instrument. This instrument has a short horizontal base ,approximately as lone as the instrure..t. Prisms at each end receive ravs of licht from the tarcet,at one end from the upzser half,at the other end fromthe lower half. Prisms at the centor,receivine these reflected rays,reflect the. arcain to the eye. she instrument is manipulate’ until tie too parts of the inace match. The ranve pointer tien indicates the approximate rence of che inate, Summary 52.Q.Ho. many meams of findi:ic raves does a battery with to. ctuncard installation possess? A.Three horizontal beses B' to 3B" B.C.to 4' 8.C.to B" Three vertical bases,one at 4.C. one at B' one at b* 37 Emeree:.cy system at emervtenc,; station. Salvo point firine. Or a totel of eisht metcods. 03. how many of these are lost with t.e Cesiruction of one station? ael.o horizontal bases and one ve.tical base. 54.Q.4%0. ~amey are lost vith ‘he destructico~ of the s cond station! a.The remainine horizont=l bare one one vertical bese. O68 FIRE CONTROL SYSTEM. (c) Duties of No.3 and No.3 (Armsetters.) 1.Q.What are the duties of “o.2 and No.3 upon arriving at the plotting room? A.To test their respective telephones, to examine their respective arms and index boxes and the azimuth circle, to sharpen pencils, and to place a clean sheet of paper upon the board for plotting when required. 2.Q.How should an arm be maninvulated? A.Grasp the vrotuding end of the arm with the left nand, ringers underneath, first and second fingers operating tne locking lever, thumb on ton cnerating the index disc clamp. Turn the index disc with tne thumb and first finger of the right hand. 3.Q.To whom does No.3's telenhone lead ordinarly? No.3's. A.No.8's telephone is ordinarly connected to the primary station reader and No.3's to secondary station reader. Wor other persons to whom either No.eé or No.3 or both may find themselves talking, see Question "Plotter 13", INDICATION AND IDENTIFICATION OF TARGET. 4.Q."nen a new target has been indicated vy range and azimuth of a predicted point, what are the duties of o.e and lio.3? A.As soon as the plotter has located the predicted point by means of the gun arm, No.3 and No.3 bring their respective arms, With index discs at zero, to the whole degree notch on their own right of the point, clamp the locking lever, turn the index disc until their arm touches the targ, then clamp, and read over the telephone to their reader the aZimuth of the predicted noint to enable the instrument at that station to ve set vefore the call,"Now" reaches the observers from the battery commander's station. 5.Q.¥hen one station fails to identify target, say 3",and "3" Relocate for secondary" is ordered, what are the duties of “o.2 and No.3? A.No.8 listens for both azimuth and range, sets the primary arm to the azimuth, and reneats the range to the plotter. The plotter plots the tarzet. No.3 brings his arm up to the targ as described above,reads the azimuth to B" reader, and then repeats to him the range from B" called out oy the plotter. SO , " PORTZONTAL BASE SVSTE™. 6.Q."hat are the overations verformed by No.2 after a target has been assigned for tracking? A.He unclamps the index diss latcn, turns the index disc until it reads zero, and unclamps the locking lever. He listens for the azimuth of the target from primary, and calls "Repeat" in a low tone if he does not catch the reading distinctly. He moves the index box pointer to the whole degree graduation on the azimuth circle strip, feeling his way into the proper notch with the locking lever, clamps the primary arm, then sets the index disc to the fractional part of the reading and clamns the index disc by means of its latch, calls "Set",then with a scft pencil marks the position of his arm on the plotting board paper along the side of the arm opposite to the direction of travel. 7.Q.What is the purpose of the pencil marks showing the successive settings of the aru? A.To detect errors in observation or reading. When the several lines are equally distant or when the distance between successive marxs is increasing or ijiecreasing regularly both ooservation and readings are free from large errors. Any sudden changes show that something is wrong. 8.9.Which are the characteristics of errors in observation? A.Once an observer is on a target he usually follows it carefully. Failure to do so may give results which have the avncarance of errors in reading. “hen on the wrong target, if the first few settings do not show it, the successive rositions of the arn will give equal, uniformly increasing, or uniformly decreas~— ing differences but the intersections made with the other arr will throw the track over snoal water, close in, or way out, enabling the plotter to quickly detect this srror and report it to the oattery commander. 9.Q.What are the characteristics of errors in reading’? A.Irregular differences between the lines marking successive settings of the aru. 10.Q.%hat are the most frequent errors in reading? A.Errore of one whole degree or of 0.1 deyree. The first is not infrequent with all bout the most exnerienced readers. It usually occurs wher. the hundredths of a devree are in the eighties or ninties because the index mark on the azimuth circle is tnen much closer to the whole degree next greater than the one which should be read. For the same reason 0.<9 is sometimes erronesualy read 0.39 on the azimuth drun. , 7” ;.lU “oe 11.9.Fow can the armsetter detect an error of a whole degree? A.He soon becomes accustomed to estimating the distance on the paper by comraring the interval vetween successive settings with the space between the notches on the azimuth circle. “hen the lack of regularity in settings is about this amount the armsetter should say over his telenhone,"One degree too large" or "One degree too small". 12.Q.How can tne reader detect an error of a tenth of a degree in reading? A.This cannot be done with certainty and even when suspected the armsetter should not ve too insistent unon his oninion. There must be no wrangling over the telepnone. The armsetter snould train himself to note how many degrees and hundredths the setting changes and then to predict to nimself what the next reading will be. Differences between is prediction and the reading telephoned may be cue to his own error in predicting, to failure to set the azimuth read, to change in sneed or course of the target as well as to an error on the reader's part. At night such errors may be due to flickering of search- light beams or failure to keep the beam acourately on the target. AUXILIARY HORIZONTAL SASF SVSTF, 13.Q.What are the duties of the armsetter whose observing station goes out of action when "AUXILIARY BASE TRACK" is ordered? A.He sete the gun arm by means of the diagonal scale azimuth circle to the azimuth called out by tne B.C. reader (by the plotter in batteries where the 2.0. station and nlotting room are agenarated). 14.Q."nat is meant by the diagonal scale azimuth circle? A.,It is the device plotted, usually in ink, near the margin of the clotting voard ov means of which the gun arm can oe set in azimuth frow its outer end. —_ 15.Q.fow is the gun arm set by this device to azimuth 359.63? A.Mcve the gun arm up to the radial line marked 359 at each end Wri na Ter: Place a pencil or pin on the diagonal line joining the figures 359 ara zero af a voint five... santns of thr diatarce petweer the 0.4 and C.4 degree lines measuring from the 0.3 degree line. “ring the Zan aru ug to this ynoint and call set. See Fic, OTN - vy _ 7,9 ' - ww ’ " as y- N . ert Tisure vwarked Piagonal Serle Azinuth Circle 7s om t ata ‘v- Ws qQ “ey oe > Ww 1:9 16.9."hby use this davice wnen vou have a gun arm azimuth circle? A.Cne armeatter is unennloyed. The use of the gun arm azimuth circle increases tne duties of either the nictter or No.l, both of whom are already busy. When firing Case IIT and clotting from 38.C.data, the sun arm must be set to the nlotted ncint by actual azimuth from 8.C. The azinuth correction having been set by No.l to enable him to read corrected azimuth on the gun arm azimuth scale, tne gun are yust be set to actual azimuth by means of the diagonal scale azimuth circle. VERTICAL BATR SveTPt, 17.9."hat are the duties of No.2 and No.3 at tho command,"R', (OR B") 1§.Q.What are the duties of “0.2 and No.d at the command,"F.C VERTICAL BASE, TRACK"? A.The ®" (cr B') arm is laid aside. The range officer [or the mlotter in his absence) throws the »ba3e line avwitclh oo that both arwsetters hear the ®' for ™") reader..Mo.2 for No.5) listens for azimuth and sets the 3' (or =") aru. No.d for Fo.) listens tor the ranee ana reneats it to the nlotter as scon as Fo.8 (or Nc.3) calls, "Set", YVENTICAT. PATE ,TRACIN? AeWO.e SGts The gun ari tO tne azimuta callea cus cy tic 7.06 reacer DY weans of the diagonal scal@? auinuen circle as ~—6deb6er ed under Question 15 avove, NO.d has no duties. Tr? TRAN ~My ayarmy ° 1S.9."hnat are the duties of Nove and ihe.3 at the conmand, "Frenarrev 2eC.Q.T3 tire any chanee in ths Gutiae 97 Ve, SVSTE*!, TRACK"? A.™o.2'3 duties are the 3am@ as at the command,"".C.TPRTICAL CASE, TRACK" When P.%,stusitn 13 9ut of commission, tne azimuth are sent from Hnwers: seney otanion to',7 who recseats them just before tne range -'o.3 has no duties, CACP T, CATR IT, ATR CASE TIT. Poor “We .5 when tna metncd cf firing cnanges from anyone of the three eases to another? A.Yo. STRVION TANGFT PAAOTION, 81.Q.%1s there any changes in the duties of "0.8 and “o.3 during service target practice as commasr*d with drill or action? A.,At the firing of trial shots the location cf the srlaahn of tie tus and of “the target are nlottea ix ths oruer named. 1/0 STRCALIZPN TALGRT PRAT™TOR, “7 v4 26.90.03 tuere any change in the duties of “o.e amd 9.3 during guocaliner target practice a3 compared with arill or action? SF ( II FIRE CONTROL SYSTEM. (c) Duties of No.5 (Deflection Computer). 1.Q.What are the duties of No.5 upon arriving at the plotting room? A.To make sure that his instrument has the proper scales updn it for the drill, practice, or action which is to follow and that it is in adjustment. For details of these adjustments, see III, Fire Control Apparatus, page J/Z7/ . INDICATION AND IDENTIFICATION OF TARCET. 2.Q.What are the duties of No.5 during the period of indication and identification of target. A.He has none. HORIZONTAL BASE SYSTEM. 3.Q.When does No.5 begin to operate the deflection board? A.As goon as the plotter calls off the second range. 4.Q.Name the operations nerformed by No.5 in the order of their performance? A.First. Set the wind arm at the "Deflection Comnonent" reading on the wind component indicator. | Second. Set the platen so that the drift curve at the range called is accurately over the right hand edge of the wind arr. Third. Set the travel arm (right edge) for travel reference number as called out by No.l. Fourth. Set the azimuth correction scale so that the travel reference number is under the normal of the deflection scale. Fifth. Set the T-square so that the point of its scale corre- sponding to the range will be accurately over the right edge of the travel arm. The bevel edge of the T-square then indicates: (a)Onthe deflection scale the deflection to be used on the sight with Case I or II. (b)On the azimuth correction scale the correction to be applied to the gun arm, when using Case III. 5.Q.Does No.l call out the deflection component reading to No.5? A.No. The wind component indicator is placed where both No.4 and No.S G@an read it distinctly from their resnective positions. few 6.Q.Under what conditions is the multiplying scale used? A."or use with systems of firing at a nredicted point which requires more than one observing interval to lay the gun in azimuth two multiplying scales are furnished with each board to be attached to the semicircular brace of the platen. One of these scales is intended for use when a fifteen-second interval is employed and the other with a twenty-second interval. They permit the making of allowance for travel during time of flight plus the travel during two cbserving intervals. All of the orerations are the same excent the fourth, which reads as follows: Fourth. Set the azimuth correction scale to the reading of the multiplying scale. Note. Since the thirty-second interval is used, the multiplying scale should be used exclusively. The platen scale is not required. 7,Q.What action should No.5 take when No.l gives him an irregular travel, that is, one which is neither the same as those which have preceded it nor regulary increasing or decreasing as compared with previous travel? A.Call "Reading lost" and report the trouble to the plotter. &.Q.Who listens to his call of his results and what does he do with them? A.“hen firing Case I or II, the plotter repeats the deflection to the range recorder over the gun line. When firing Case III, No.5 himself sets the azimuth correction on the azimuth correction scale, (C.A.D.45.4°4) ,and calls off the corrected azimuth (See C.A.D.R.490).The plotter tran- smits the corrected azimuth to the guns. CAUXILIARY HORIZONTAL BASE SYSTF*. ' 9,.Q.Are No.5's duties affected by a change to this system? A.No. VERTICAL BASE SYSTEM. 10.Q.Are No.5's duties affected by a change to this system? A.No. EMERGENCY SYSTE?. 11.Q.Are No.5's duties affected by a change to this system? A.Not as long as the nlotting board remains in action. SFRVICE TARSET PRACTICE, 12.9.Are the duties of “No.5 different at service target practice from these at drill or in acticn? A.He must see that he has the service leaf range scale ard the service T-square scale in place and not the subcaliber scales. The operation of the board is the same. SYBCALIBER TARGET PRACTICE, 13.9.Are the duties of “No.5 different at subcaliber target practice from those at drill or in action? "A.He must see that he has the subcaliber leaf range scale and the subcaliber T-square scale in place and not the service scales. The operation of the board is the same. Sl. Il FIRE QOYTROL avenr (c) Duties of No.6 (Gun communication detail). 1.9.™hat are the duties of No.5 unon arriving at the nlotting room? A.To inspect and adjust his instrument. For details, see instructions for the instrumei.t unaer III Fire Control Anvaratus—-Communications. 2.Q."hat are No.S's duties during tracking? A.To transmit to the guns the corrected range announced by the plotter. (C.A.D.R.4¢5). 3.Q."“nat are No.S's duties during tracking when the plotter wears a telechone head set to the runge recorders? A."e is usually employed to record cata sent to the guns, his record being used to checx up and fix the resvonsibility for errors. | . 4.Q.Are these duties affected by anv change in the system of firing or of tracking, or, from drill to target nractice or action. A.No. Except that when the nlotter's line becomes unserviceandle, he transmits the range and deflection or range anc corrected azimuth to the guns oy the auxiliary means of communication. . a “iw TI FIRE CONTROL SVSTFM. (c) Duties of No.7? (Emergency communication detail). 1.Q.What are the duties of No.7? upon arriving at the plotting room? A.To inspect and adjust hisinstrument. For details, see instructions for instrument under III Fire Control Apparatus-—Communications. 2.Q.What are the duties of No.7? during tracking? A.He keeps a record of the ranges received from the emergency station and calls these ranges to the plotter when the emergency system is used.(C.A.D.R.496). After the B.C.station is out of action, he repeats and records the azimuth received from the emergency station which will precede the range in the message. 5.Q.Are these duties affected by any change in the system of firing or tracking? A.They are unaffected by changes from one system of firing to another. They are affected by changes in system of tracking and by action only as indicated above. Me Plotter. Il Wire-control svsten. (d) Emergency system and salvo noints. Note:- This is also vart VIII fd) of examination for Cun Commander and Gun Pointer and vart II (c) for Observer. L.Q.Define"Fmrercency condition" ."Emercenov syste" A.A term to denote damnaze or assumed dumage to any element cf coast defenses ,rendering “it, or assumed to render it,out of action for the time being.C. G.ALD. FR.1053, The vrosition finding system used in our service includes- * * * * * * * x ° * * * * * * * * * * * * % * * * * * (c)The emercency system,which ordinarly emrloys a self-contained instrument located at the battery,vith or without a nlotting roard.C.A.D.R.1S9., 2e.Q.What equinrrvent is furnished for the enerrcencv station of a oe inch battery? Yor batteries having the equivment of a batter of the primary armament? A.Self onntained range finder,usually of the Rarr & Stroud design. Azimuth instrument until self contained range finder is available. Time interval recorder (stop watch) Speakinz tube to plotting room. Megaphone. Salvo table. Orientation table.(See table VII,C.A.M.No.4-190S). Batteries whose fire control equipment conforms to that of batteries of the secondary armament are not equinped with an emergency station. Artillery Bulletin No.94,April 17,1913 contemplates firing under emergency conditions vceing conducted from the mo¥st available point after the B.Cc.station becomes unserviceable, 5.Q."hat personnel is required for the emergency station? A.Observer,and assistant observer. 4.Q.When is the emercsency system used? A.When failure of communications or damage to 8' or B" renders it necessary,or when the change is made for drill or target practice. 5.Q.Fow is the transfer from other systems to emercency system acconiplished? A.The battery commander orders it and the range officer commands, EMERGENCY SYSTEM, TRACK.C.A.D.R.502. 117 6.Q.Why is this action on the nart of the range officer necessary? A.Because the battery cormander has no way,excent by meganhone,to reach the emergency 3tation. The sneaking tube runs from the plotting room to emergency station. 7.Q.Uow is the data from the emergency station transmitten? A, _ (a) Plotting room serviceable. | The assistant observer at the emergency station transmits the ranges to No.7 who repeats them to the plotter. (bd) Plotting room unserviceable In case of damage to the plotting room,ranzges as read fror the emergency instrument may be megarhoned or called through the . speaking tubes directly to the gun platforms.(C.A.D.4.503.). 8.Q.Does the emergency detail track all targets. A.Yes. 9.Q.Does the observer send all data to the plotting room or only that obtained after EMERGENCY SYSTEM has been ordered. A.He causes al} obgservations to be sent to the plotting room where No.7? records them for the information of the range officer. When Emergency System is ordered the ranges are repeated to the plotter. 10.Q.From what sources are the azimuths of the target obtained where EMERGENCY SYSTEM is ordered. A. (a) B.C.station serviceable. From the 8.C.instrument No.2 of the plotting detail sets the gun arm,using the diagonal scale azimuth circle. The Plotting proceeds as prescribed for the vertical base system except that No.3 has no duties. (b) B.C.station unserviceable. The B.C.observer transfers the azimuth instrument (unless one is already there) to the pier mount in the emergency station, levels and orients it as quickly as possible; he observes and reads the azimuth of the target at each bell. These azimuths are transmitted by the assistant to the plotting room in advance of the ranges read from, the emergency instrument.(C.A.D.R.502 Azimuth can also be readathe Barr & Stroud self contained base instrument. 11.Q.Define "salvo voint"? A.A selected point at which fire is to be concentrated.(C.A.D.R.326 To order restricted fire,he (fire commander) may give any of the following commands: BATTERY ,» BATTERY COMMANDER'S ACTION. This places the action of a battery entirely in the hands of its commander (C.A.D.2.545). Lh 12.9.Does the abvome regulation mean that the guns are to be disch- arged at the instant each vessel passes the designated salvo point? Explain. A.MNo. It means that the nieces should be discharged at the proper time for the projectiles to reach the salvo point at the in- stant the target arrives thpre,that is the battery should fir the time of flight before the target will arrive at the salvc point. 13.Q."hen is the exact determination of this time important and when is it not? A.It is important when firing at a target coming in head on or when retiring in the onnosite direction because the travel of the tarzet affects the rance almost altogether and has little effect on the deflection. The difficulty under normal conditions of making a hit for deflection is very much less than that of making a hit for range. Even when the sight is disabled,the gun can still be laid in azimuth under cover, all necessary travel corrections being made on the plotting and deflection boards. The higher Yrobability of obtaining hits for deflection is not more than offset by the fact that under the above conditions the gun vointer has but the width of the vessel in which to place his shots instead of its length. It is not so important when the travel of the target is almost entirely in azimuth. The range changes are small and easy to estimate,should the condition of the fire control] system vrevent their accurate determination out it must be recalled that now the range disversion of shots must be much leas to insure hits since the shots must strike from a very small distance short of the target to the far side of the dec while before the same height of freeboard and the whole length of the deck was vresented in the direction of range disversions. 14.Q.What is the best location for salvo »noints? “hy? A.At mid and short range because the fire control system will re- main serviceable for long range fighting Mid and short range are the only distances at which salvo noint firing can be forced unon the defense or at which economy of ammunition and gun life would make it advisgable to fire by this means. 15.Q.Under what conditions does the angle at which the ship presents itself at mid and short range favor hits? Under what con- Gitions is it3 “resentation unfavorable? A.At mid range the target is usually forced by the channel to pres- ent its longitudinal axis at an angle to the battery while at short range it is usually broadside on. This favors hits wher the greatest error is due to difficulty in determiming either range or range change. “hen the guns are badly worn the powder erratic or the perscrnel inaccurate or inexperienced in laying tae gun3,the presaniation of she target would ve unfavorable to hits. 119 16.9."here is the salvo noint data nosated? A.It is customary to stencil it on the emplacement wall. 17.Q.'inder what conditions ill firing at salvo points usually ernloyed? A. “iring at salvo points may be ordered oy the battery commuander or higher commander when - (a) When, in order to conceal the strength of the defense, firing is not to commence until just before the target reach- es a certain salvo ooint. (o) When,under emergency conditions, it becomes necessary to fire guns by salvo data. There will be two stages of firing under this condition. (1) Position finding system unserviceable and sights serviceable. (2) Position finding system and sights unserviceable. 18.Q.How will firing be conducted when some form (horizontal base, auxiliary base,vertical base,or emergency) of the position finding system remains serviceaole but the sight has been rendered unserviceable, A.By Case III. 19.Q."hat should be done when only one sight of a battery becomes unserviceable? A.It would vrobably be advisable to send deflection to the guns whose sizhts were still serviceable and corrected azimuth to the gun with unserviceable sight. This would depend uvon tne skill of the rersonnel. It would be better to send corrected aZimuth to all guns than to eliminate one gun entirely. 20.9.Who would order salvo point firing under condition (a) in Questior 17? Under condition (bd)? A.Some commander higher than the battery commander would be the one ordering it under condition (a). The battery connander would be the one to order it under condition (>) since higher commanders would not know that the battery had been reduced to this extremity, excent after report had been mad from the battery. 21.Q.Would it be advisgable under condition (a) to interpret the order, during action,as requiring firing by salvo pgint data or simply as indicating the stage of the engagement at which firing wae to begin. Aw FEC A.It should be intervretdd in the latter sense,since to begin firing by salvo noint cata,would be a complete sacrifice of all the advantave cf the fire control system to slavint. adherence te the vrrimary military rule of obeving orcers. Tris is a case where obeying the snirit of the order would be much better than obeying the letter of it. Firing should proceed in the normal way after the battery cormancer has assured himself that the first vessel has reachen the desif- nated salvo noint. e2.Q.Srould the battery coniander intervret the order strictly during drill? Why? A.Yer. The higher com.sander probably desires him to drill as if his battery were reduced to condition (b). 23.9.In the licht of Question 61, is it advisable to require the plotter to rredictyas in the mine system of plotting, the time for firing from the observed travel of the shir? A.No,since firing by salvo roint RATA will de conducted from , . a. ~~ > - e - e . ° e Yhe first kind arc discissed uncer Plotter, TI\L) Incvication ana Identifi- cation of Targets, Question 41, page?2. It is a fortunate coincidence “nat thie points weic’. favor t:-e considerations *fectinge tie abilit; to see, cive a fairly satisfactory, adjustment for tye center of imnact. Assurc the U.S. battleship Delevare as tie tarcet, 516 feet lone, €5.<5 foor beam, 2% foot draft, firs*?"hexuc on” and then"stcrn on" to tc battery a‘ rances of @€C00 anc «8@0C yarcs wecre tre slope of fall is respectively 1 on 4 aw 1 on 10. If the ship nas a free Loard of 30 feet, then the equi- valent vertical tar:et is for “head on", ranze €CCO, 30 feet for free- board plus 147.5 for acck canjer space, or 157.5 feet. With the observ- ing; point at the waterline at tic foot of the foremast, this vertical tarret is diviced so that one third is below the trajectory which just reaches the observins point, i.e., the trajectory havins zero longitudi- nal ceviation, while two thirds of tne tar:ct is above this trajectory. On pase 38, Regulations for ti::e Instruction and Tarset Practice of Coast Artillery : lyl3, we find that tre probability of hitting tne material target, height 30 feet, is 14%. From Major Hamilton's Notes on Ballistica pace 287, Journal of the U.S. Artillery, Nov.-Lec. 190¥, we find that for a probability of 14, the target is but 23% as wide as the 50% zone (the zone in which one half of the whole number of shots fired may be ex- pected to fall), hence we conclude that the vertical 50, zone at this range is 115.4 feet wide. Referring to the upper view of the veleware [Bd on the sketch, AIMINU AND OBSERVING POINIS, we find that the third of .u. the equivalent vertical tarret which is below the trajectory to the observing point, 0, is ¥0.&% as wide as one-half of the 50% zone. Re- ferring again to Major Hamilton's table we find that the probability for this width is 46%, i.e., 46% of the shots which fall short will strike the ship if a reasonably larse number of shots be fired. Similar- ly the two thirds of the equivalent tarcet above the trajectory to the observing point, 0, should be struck by 78.1% of the overs. The expec- tancy of hitting the VLeleware without an adjustment for center of in- pact under these conditions will then be the mean of these two percen- tages, or 62.0% Now if we adjust the center of impact so that it will fall in the center of the equivalent vertical target, we find by the same table that our probability of hitting is increased to only 64.2%. If the Deleware were stern on (not show on sketch), the trajectory of the perfect shot would divide the equivalent target into a lower part of 62.5 feet and an upper part of 95 feet, giving probabilities of 53;37, and 73.4. respectively or an average of 63.4 for both parts without any adjustment for center of impact. When the Deleware is"head on” at 4800 yards (not show in sketch), we have an equivalent vertical target of 7.5 feet for ricochet danger space plus 30 feet freeboard plus 51 feet for deck danger space, or a total equivalent vertical target of 88.5 feet divided by the trajectory of a perfect shot to the observing point into a lower part of 38.5 fect and an upper part of 59° feet. Our probability against the material target, height 30 feet plus 7.5 feet for ricochet danger space, or 37.5 feet, is given as 80, in the Regulations for the Instruction and ‘larget Prac- tice of Coast Artillery : 1913. From this we find by the same method as before that our 50% zone at 4800 yards is 19.72feet high, that the lower part of our equivalent target shoula be struck by 99.5% of the shots alling short, while the upper part of the equivalent target is somewhat wider than necessary to give a probability of 100% of the overs hitting. Without adjustment for center of impact, the expectancy is then $9.75, of hits. If the adjustment of the center of impact be made, the equiva- lent vertical target is found to be somewhat wider than necessary to give an expectancy of 100... When the Deleware is "stern on" the equivalent vertical target is practical- ly the same ae before since the lower freeboard is partially balanced by the greater ricochet danger space. ‘the trajectory of a perfect shot to the point of observation divides this target, as shown in the sketch, into a lower part of 32.5 feet having a probability of 97.33% and an up- per part of 56 feet which is wider than necessary for a probability of 100%. Without adjustment for the center of impact, the expectancy is then 98.67%. As in the case of the "head on’ position, if the adjustment for center of impact is made, the equivalent vertical tarrcet is found to be somewhat wider than necessary to give an expectancy of 100p. When the Deleware is "broadsice on" at the long rance, &C00 yards, the e- quivalent vertical tarret is 30 feet hirh for freeboard plus 21.4 feet for deck danger space. The trajectory of a perfect shot to the observine point divides the target into a lower part of 10.7 fest navin- a prob- avility of 10.25% and an upper part of 49.7 feet havinz a probability of 35.33f~. Without the adjustuont for center of impact, the expectancy is 23.3% wiile with it, JP5iS*PhEGa8Sa to 23.75%. “nen the beleware is ‘brouasice on at the short rane, z:8CQ yards, the e- quivalent vertical tarset is 7.5 feet for ricochet dancer space plus 30 feet for freeboard plus &.5 feet for deck danser space, or a total of 46 feet. The trajectory, of a perfect shot to te observing noint, 0, Ai- vices this tarset into a lower »art of 11.75 feet havine a probability of 08% and an upper part of 34.25 feet having a probability of $&%. Without an adjustment for center of impact,the expectancy is 78%, while with it,the-expectancy is 88.8%. 21.Q.Why is no allowance made for ricochet hits at 8000 yards? A.Because the range is beyond the 60C0 yard limit where ricochets may be expected. See question 12 above. 22.Q.nat is the probability of hitting a 30 by 60 ft tarvet at these rances? A.At 4800 yd-80% 8000 yd-14% 23.Q.What is the probability of hitting the above battleship with and without the adjustment of the center of impact? A. Ranse Position Provability Yards of ship. Without adjustment With adjustment 8000 Head on 62% 64% 8000 Stern on 63% 647, &000 Broadside on 23 3% 23.75% 4800 Head on $Y.75% lec .% 4800 Stern on Y8.67% 100.% 4800 Broadside on 78.6% E8 8% 24.Q.\7ill any othor shots be hits? A.A few shots fallin: short misht be close enoucsh to sive underwater hits and a few over micnt hit the upper parts of the masts and funnels, par- ticularly when the ship is in the "broadside on" position. Hits of t*is Kind are not to ec relied upon cut accepted as offsets for misses on accouit of errors bt, the personnel. 29.Q.What is the permissable variation in ranje dispersion in the thres cases shown: A.At «800 yards, 295 yards tt 4° OC " 153 " At 8000 yards 210 yards 6&5 26.0.How far may a shot be short,or how far over and still be a hit wnen no adjust of center of impact is mace? a.eRance Position Over vhort | ya. "de 8000 Herd on 140 70. BOO Steim ou 126.7 83.3 8CoC Broacsice on 552 a¢/ 142.7 E02 Head on 166.1 L283 4E&OR Stern on 180.7 108.3 48C0 proacsice on 39.0 t def /; ff es 27.2..nere shoule the oxservin, points be for a ship "broucside on" to tie battery? aAeln tne same place as for ov:er positions. Sec sketch of the Deleware. 28.Q.Upon what point shoulc the sun be laid in deflection? - +7 t! A wUpon the verticul centerline of the tarcet for ‘the "head on " or "stern on " positions. “nen the tarcet ap-rouches close enou_h to be "broad- sice on " the sun pointer should tien be laying on selected voints. #'o. reavy suns,this snould te the Lelt amidships,a particuler turreéet,the connins tower or ot'.er heavily armored part. For intermediate suns,t*o sun should Le lait on that pertion of the ship siven to armamer.t of the same caliver,on sivneal stations,searchlisnts at nicht,ete. Seconc- ary armanant would onl. Le employed acainst armorec ship in an extremity. 29.Q.Will the rance for the observing point in the " broadside on " position be proper for these selected parts. A.Yes, All parts on tre eenterline have almost exactly the same ranse from tne battery. See discussion on tne ansles of ship presentation to the line of fire in questions 13 to 15 inclusive under Plottcr,II tire Control System (ad) Emerrency System and Salvé Points on pace 6 . yy : 30. Q.What are some of the causes of vari ions in muzzle velocity? A.l.Variations -2,Variations n strength of powcer due to are; n manufacture; 3.Variations rate of burnins upon discharce; 4.Variations in temperature of povder; 5 Variations in weight of char-e; 6.Powder in different charges not uncer uniform condition of storace; 7.Black powder igniters damp or caked; &.Variations in weight of projectiles; Y Variations in coniition of rotating bands; 10.Yariations in ramming; 11 .Variations in temperature of sun; 12.Condition of bore. fe pte fale pale rs 31.Q.How are these variations el&minated or minimized? A.eCauses 2 anc 3 are controllec by careful insrection durin: manufacture. Causes 1,4,6,7,ard 9 are controllcc principally by the care exercised in handling ana inspecting while in storage and in the selection of the lots to be fired. Causes 5,and 8 are entirely within the personal control of the battery commander. Carelessness in handling preparatory to practice will affect causes 4,5,6, 7,8,and 9 enouzh to seriously affect practice. Cause 6 is neutralized by careful blendinc. Cause 10 is minimized by careful drill. Cause 11 cannot be avoided but affects only the first few shots seriously. Little account of it is taken in practice. Cause 12 is,aside from the question of cleanliness and freedom from rust, a matter of the age of the gun relative to its effective life. It doe. not cause serious variations from round to round with broad banded projectiles until the number of rounds fired becomes excessive. she most important to an artilleryman are those affect the round to round variation since corrections can be made for the others. Considerins No.6 to mean care in blencing the causes important to sood shooting in any one practice are Nos.4,5,6,7,8,9,10,and ll. Mus2ete—Yetoctt . were 32.Q.#or which of the above condition ipmase cirectly on the rarse board? A.#or known or assume’? variations in muzzle velocity Yor variations in strencit. of power Kor variations in manufacture of powder ror vabiations in rete of the burn'rn:; of powder For condition o7% bore une last four affect the muzzle velocity directly and are measure in temns of muzzle velocit:. 33.4.¥"0r which of tre aveve coneivions ma; correctic..s Le eace indirectly on tee race boars? ator vari:itions in Vic weicht anc form of projec .le. For variations in tenperature of povre- 34.2.For vhic: of tee above coneitions cai io Cuervevesel ou Mace on Dts rani 2 hoard? AeFor variatioss inwoicht of charces. For variations in Ciaseter ant coat ition of rotatia-~ bands Por veriations im lence’. of travcl of proie. tile in hore For variatio:s in rai inn 39.,.4ow is *:e@ variation in ~uzzle veloci*t; due to a variation 1. weics. of charce Go termine’? Is it different for elf creat ra ces? weBy “ne forsvala: 6 Dey in wick i ote’ A indicates the j 4 V = V,in woich @ =weim’.. of charze and licicates whe increriecs. fivcrea e Y. decreaso in the value.) nis formula is applicatle for small variations only. Amore exact forsula is that siven in C.s.7.5.796: v = “ VT ms 4 * 147 (7) » wrere V and.’ are the normal muzzle velocity anc the nor- mal weix~ht respectivel;. The averare value of 3 is: for nitrocellulose powier, 1.2; for nitro glycerine pow'er, C.& . Differences i> roen-es (elevation of un) can have no affect upon the aroun: of enervy cuveloped by a power. 36.Q.How much will the muzzle velocity be affected by a variation in weight of L pound? A.6 inch -un podel of 1897 M Tw = 29 pounds M.V.= 860¢ ft.per second. Av = : 29 2000 = 1¢7.5 ft per seconc. 37.Q\.How is the variction in muzzle velocity due to a variation in w: oe “ht of projectile determined? Is it different for different rances? by the eS AV= AY V,in which w = wt.of projectile lhe range Corevate on of gun) has nothins to do with muzzle velocity but at any point alons the trajectory the remaining velocity will vary from the normal remainins velocity,being greater for heavy projectiles startinr with the same muzzle velocity. In other words the flight in air of projectiles of different weichts partially counteract the chancse in muzzle velocity due to the same condition but tne effect of tne variation of weight on muzzle velocity is predominant. It is not a service condition for the muzzle velocity to remain the same for projectiles of different weight. 38.Q.How much will a the muzzle velocity be affected by a change in weight o1 projectile of 1 pound? A.6 inch gun,model of 189’ M I w= 106 lbs. M.V.2 2600 ft.per second. AY = - pet RE- 2600 = 10.73 ft per second. 39.Q.How may the effect on the remainins or striking ve'’ocity and the ranre for variation in weiz!t of projec*iles be determined? A.the so-called atmospnere curves on the rance board are really curves representing variations in the ballistic coefficient ( a factor showing the ballistic efficiency of the projectile and involving effect of atmospher&c density,form of projectile,its weight,diameter, maxirmm altitude of trajectory,etc). the reference number 16 represents the value of the ballistic coefficient taken as standard. when any one of the above conditions produces a chance,the percentare of change is represented by the reference numbers. Thus a + 10 4% change in weicht of projectile,hence a + 10% chance in ballistic coefficient is represented by the reference line No.26 while a simila: negative chance is represented by reference line No.6. 40.Q.Is the correction of the muzzle velocity for difference in weizht of projectiles sufficient? Does it take into account the partiully compemsating effect of the variation in weight while the projectile is in air? A.lt does not. ‘the correction for the latter effect must be made on the atmosphere curves. eg PLOTIER, IV Elcomentory Gunnery. \b) Nffoct on the flight of the projectile of varations in ~he density o° the cir: the direction znd velocity of *he wind. Under this subicct will be Ciscussed the deflection corrections only. all runce corrections were discussed in the preceding subject IV Ga). 1.Q.For what are deflection corrections recuired? AeFor vind dmift anc travel of the tarect, 2 eel the eun polnter appl, a ceflection correction for an observed error? Aeains ~All be laid for raunee upon cuta furnished by the deflection boar? only; unter no circumstances will cun pointers apply any other dcf- lection correction. Reculations for tte Instruction and Tar:et Practice of Coast arviller, Troops : 1912, 2.6 orerly re xept Sun and crosswire on the targe$ until he saw the splash wien vravorsed crosswire fron target to splash, then gun and cross- wire back to splash. See C.A.DR. 675 an? 676, also "Okserved Error" On upper diacran of plav., Elementary Gunnery and Yiarships under Plotter IV(af, facing pase /Z 7. 3.Q.“hat is draft? ae See Definitions in Appendix A. #.Q.ishat are the cordj.tions which affect the density of tne air. How? A,ltemperature as shown bt. the thermometer. atmospheric pressure as shovn by the barometer. As air becomes heatec it expands and becomes lighter. This is the reason for hot air rising and for cold air setting as exemplified by the risins of a balloon filled with hot air and cases and by the setting of cold air alonz the bottcm of ravimes and gulies at night. — : we are at the bot*om of an ocean of air some fifty or morc miles in depth, Like the ocean of water this ocean of air has eomperativeliy pressures at its bottom vastly greater at the bottom than at the top,about 14. pounds per square inch at sea-level and next to nothins near the top,due to the weisht of the air piled up above the bottom layers. Thése oceans of water have this same pressure of 14.7 pounds per square inch at their surfaces with several tons to the square inch at their béttoms. Ihe ocean of air is akso like those of water in that it has its waves, much higher and farther between than in water.its warm currents anu cold currents determined by the shapes of its ceeps and its shoals, its great movements somewhat similar to tides.and its eddies and and counter currents,these last beinre of greater extent and more rapid in their movements than the same things in water. SeQevhich of these charactsristics affect the atmospre:ic pressure as shovn by the barometer? AeAll of those whicn increase the heicsit of the air piled up above us and the weisht of that air per cubic foot or per callon. 6.Q.which of these characteristics give rise to wind? A.All those which produce air currents or edcies anc swirls. 7.Qevhat is the effect on the flight of a projectile of the variations in density? Aslhe greater the censit, tne more the atmosphere will resist the flight of the projectile. Variations in resistance produce the effects shown belows Increase in resistance, Decrease in resistance. Velocit: falls off more quickly. ~ Velocity “old up locer. Smaller striking velocity Greater srtikine velocity. Projectile does not so as far Projectile coes farther Gun must be given greater elevation. Gun must be civen smaller elevation. Wun must bo viven increased rane Gun must be given decreased correction. ranse correcilone Trajectory more curved Lfrajectory flater Greater anvls of fall smaller aicls of fall. Chances in censit,; of air have no appreca&able effect upon drift. B8.Qewhat effect has te direction and velocity of vince upon dcefleciion!? Aetne direction may perhaps te said to te the more important of the two since a strone wind blowing directly; with or against the projectile has no effect upon deflection while the deflection is affectec by very moderatr cross winds. The ereuwt er the velocity the .ind the creator the deflection when the direc*’on is such that the wind has any cross (deflection) conponent upon thewind component indicator. Careful study of that instrument is a first essential to graspinz the principles involved under tnis question. 9.Q.How is a correc-ion for drift applied? A.eMuzzle and 3 point on deflection scale in the opposite direct on-to the left in our servicc excepy with mortars firiins at the hicher elevations. e e . . . © Deflection always reads-2 for l of drift,i.e.l less than the normal 5 ® readins 3 ; 10.Q.How is a correction for wind applied? A.Itizzle anc 3 point on deflection scale move into the wind. Cross wire moves with the wind. ‘think of it as the light cross wire heinz> blovm across the deflection scale with thevind. 11.Q. 43: 11.Q.Hoy is a correction for tr:vel aplied? A.Muxzle anc 3 point on de“lection scale must be ahead of the tarcet when cross wire is on the tar et. If you would kill a goose don't sh.ot for where he is but shoot ahead of him for where he is céinc io be. Note: whe figure at the top of the plate on Elementary Gunn ry and warships shorn the effect of havins wind,travel,ani drift all actins in the same Cirection. Sre heavy line markcd"Drift Curve" shovs how the drift throws the trajectory to the right ana is itself the trajectory when no wind is blowins,The Sroken line G3' shows the axis of the bore moved to the left the emourt necessary to correct for the drift. Similary the lis mark d "srajector:" shows the position of the trajectory when acted on by both the wind and the drift. The cistance of the trajectory to the right of the arift curve shows the amount the wind throws the trajectory to the right. the broken line G3" shows the axig of‘the bore moved to the left to compensate for wind and drift. whe broken line target is the position the tarret has reached at the end of the time of flight, Therefore G3" is moved to G''' ahead of the tarset so that the distance between G3" ana G3''' is equal to the travel of the target. G3''' is the final and correct position of the axis of the bore for hittine the tarcet in its advanced position, The lateral scale (of deflection) of this ficure is great as compared with the longitudinal scale (of ranves) in order to make the fircure clear. False conclusions may ve dram unless this fact is corne in mina. This diagram is intended to emphasize the fact that the 3 point on the deflw tion scale and to axis of the gun always stay to:ether. Look over the 3 point to see vhich way your muzzle is pointing. The splash of the shot is indicated to bring out the " observed error’ and the difference bet. tween line of shot and line of airection. IV ELEMEN:ARY GUNNERY (as) Use of trial shots and application of data obtained from them. ( problem) PROBLEMS Condition x Cal.of Gun 6° Temp.of power 70 Atmosphere Reference No. 20 Wind " " 70 Vel.assumed, f.8. 2530 Range to ‘larget lst shot 5830 oe ee ee 2nd ve 3840 tt rr " 3ra " 580 " mo" 4th " 9865 Side of target on which tug appears right Range of tug from battery compared with target shorter Angle of tug-target line . with line of sight. 99 Distance tug to target yards 375 Range deviations in mils from tug ist shot ~540 Change in range after lst shot +300 Mils,2nd shot #215 "3rd " +180 a ath 9 - “0 Deflection yds. lst shot LoL and "* 2a L 3rd” 11 L 4th " Li L Find muzzle velocity to be assumed for record shots. +5 =3 42 #2 IT 6" 65 12. 30 2587 6490 6480 6460 0470 right longer 029 410 60 00 90 ‘22 +210 fo ~a to fo DDD wD on ITI 6: 62 18. 80 2473 7310 7350 73.0 71340 left longer 78 335 IV 6 73° 13. 40 2512 4530 4940 460 +580 left shorter 50 355 Plotter i VY Prevaration of turset-sractize records. Pant See notes cn forms surnlies for this rurvose By the 7ranerce Devartment. The following roint is not well covered and the list voelow will be of srecial assistance in this suvject: Q. Uow is the"actual range, piece to ta t reet" deternined from the "corrected ranze at which the riece was fired". . A A. Deduct the following: “1etaxnegs in settinz; " " transmission; " on vlotting doara; " "rarce board; Travel correction for uncomrleted rart of interval; Fictitious nart cf rance correction, 1.e., correctior fa wind, velocity, tide,atmosrhere, and adjustment for cpr center of inact. S36 I Definitions C.A.D.A. See questions indicated in"O°BERVER "column in anpendix A. Elementry gunnery definitions are illustrated on Rlementry Gunnery and Yarshivs diagram under Plotter IV Flementry Cunnery (a) Explanation of the several corrections ts be arslied to the observed range to obtain the correctdd range,facing page £7 . OFSE VER, IT Fire-control systen. (a) Detailed desorintion of that in use at the battery. For this subject,see the same subject under Plotter II (8) age’ Coserver. II Fire-control systen. (ob) Indication and identification of targeta. 3 1: Lt . . . wv “or this suoject,see the sare sudject under Plottey II (0) ye? ORSERVER, II Fire-control system. (c) Emergency system and salvo noints. For this subject,see the same subject under Plotter TI (d), Auge /, cd SFO III FIRE CONTROL APPARATUS. (a) A detailed knowledge of adjustment and use of all ovservins 1.9. Candidates shoula ni Nane AZimut Tow 2.9.: A she 18s S _ . 4 “as a. $ sf such yuastt instruments and ran ca finders in use at tre dbatterv. WARMER &% SWASEV AQ TMITH [TNSTRIPEENT, Models of 19C0 and 198C0 "AVI. tired to answer yuestions marked Tf they elect to answer anv or all 2 Ls thus * in org3r to pas . ° e® additional credit should »e fiven. 4 that an azi:gath instrument chest shucula h instrument ,olum) 900 and cord,ctin wrench and screw-driver . should a trivnod be set un on a flocr or concrete surface? e in cracks of the floor ,small holes in tne Jd oD aad into a wooden floor to cive them a hol The ese should not oe s: read TOO much e tendency to glin. Ynen set un on the “round Che ‘less sho ald be thrust into the soil indivia- veallvy until a firu Dearing i838 secured. “tnerwise the instru- ment will be shifted by the overator sternning too close to the legs. ‘the tripod head must be anproximately level before the instrument i383 nlaced on it, hx rare 2 OD wm 3 Cs Ja © i a S ct oO 3 rv) o 2a ct 3.Q.Fow should an instrument oe grasned when removing or returning A.Place the hands wun: it to the chest? “hat nrecautions are necessary in securin; fhe instrument to the trinvoa or pier mount? In renacking it in the cheat? Illustrate. lere-eneaty the nlaten. The telescone is not intended as a hanile. tts use for that nurnose will injure ) its adjustwrent. When. acrewing the instrument on or off the trinod,it must %e@ sunsorted by the hands while giving the base the necessary motion. The base should not he set un too secureély,lest ther? be difficulty in renoving it. Eefore rerlacing the instrument in the box,care should be taken that all screws be firmly clamred,to avoid damage in transit. The telescone sahould be rlaced lenzthvise of the box, ,eave riece to the left when facing the chest, 14 / A.Q.Level the instrument? Degcrive the nrecesst, A.See that all levelling screws are hearing snugly. Nisengace - the worm by means of the worn box eccentric crank. Set ine ® telesconve rarallel with anv two diametrically onnosite ° levelling screws. Srasn tvo diametrically orrosite levellirn,: 3 screws vetween a thimd and fore finger. Tarn oth screws Y inward or ocutward,that is,in ornosite directions; never in “ the sane direction. Turn the left thumb in the way the bubble 3 should go until the bubble comes to the center. Adjust the + other cair of levelling screws. Tf the two levels are in : adjustment with each other and with the vertical axis of the instrument,the instrument is now levelled. The adjustnent of the levyela should always be tested as indicated in Question Bix below unless it has been very recently tested. §.9.Pescribe the joint between the snindle and the base ard the reason for thi3 construction? A.This joint is of the ball and sacket tyne rnernitting movenent in any Girection excent radially. The bearing surface of the Brindle is snherical and fits in a spherical surfaced soczxet in the base. See Class 35 Division 638 Drawing 25 in Ordnance Pannhlat No.1l65”. 6.9.Vhen the levels are out cf adjustnent,how are they adiusted? A.To test the levets to determine whet adjustrent rroceed as roltows: % bubble to the center of the bub levellins screws. Turn the teles e in azimuth 180 decrees, If bubble remains in the center,tne bubble axis and vertical axis are rernendicular to each other. If the bubble does not stay in the center, correc: one half bv means of the levellin; gorew3 and one half? bv the level -. older acrews. Reneat until bubs Ts retains stationary. “ith the sane les el preneat cver the other wair of screws unti axis and one level are now rervendicular to each other. To bring the onan leval into a ljustrant ,atinat i+ by cernarison with the vel fir3t selected. “ake the full correction on the level ho lder screws. : ner or not thev are out of ot one level. Pring the le tube by means of the ar e ao l gatisfactoryv. he vertical 2 oO a Note:— To vrintergone under line means for that nart to ¢o in italics. LOL fo ate, 7.Q."hy do you correct for one-half of the error in one place and half in another in adjusting the first level ard correct all of the error in one nlace on the second level? A.See sketch,"Adjustment of Level Bubhles". “uch of te difficulty in grasving this princisle will be removed when it is recognized that neither level or vertical axis can »e.in its prover positio: when the other is out. In other words the bduobdble can stand in the center of the curved »dubble tube only when both the level and the vertical axis are in adjustment,or both ont by the same amount. The error of one exactly counteracts the other in the nosition \ B,while both errors combine to give an annarent error of double the real amount when in the position A'SB', The first level having been sut in adjustment with the vertical axis,the second level must receive the full correction or the first adjustment would oe disturbed. This having been done,the two levels and the vertical axis will all »e in adjustment with each other. : P.Q.4hat is the rnane c® this inetrunent? A.Azimuth Instrument,'iodel of 1900 (or “Model of 1900 “% I.) made by Warner & Swasey. ana 9.Q."hat is the difference between the ‘indel of 1900,‘fodel of 1900 XM.I. S.Model Prisms Focusing Lamp Dew Part Bracket Can <2 1900 BrashearObjective *ixed No MYastings. 1900 Porro Cross- Movable Ves M.I. wires Model Obdjective®ocal Power Field aperaturelength of view inches ances Degrees 1900 1.5 11 6 4 1900 1.5 11 8 4 MoI. 10.9 .What does a oier mount look like ana when is it used? A.See vart 100 on Class 35 Pivision ce Drawing 25 in Crdnance Pamphlet “o.1€57. The nyramidal snaped bolt is sunk in soft concrete. The Sase i3 laid over tre bolt after the pier is hard and then secured in place »y screwing the nut on to the bolt. It is used where a permanent and stable mount is especially desired,and .in observing stations and emergency stations where the aZimute instrument is a rermanent part of the equipment. 11.9.Draw an outline of a set Brashear-Yastings prisms? A .SeeFig. (Take from Coast Artillery School Pamphlet on Optics figure —- 12.Q.Eraw an outline of a set of Porro rrisms? A.SeeFig. (Take from Coast Artillery School Pamphlet on Optics figure 13.Trace the rath of a ray of light thru each kind of prism. Show Low the image is erected? A.See Figures and i Take fronCoact Artillery “School Pamchlet on Optics ( figure __). 14.9."hich tyre is the most difficult to make? Why? A.Brashear-Hastings. Secause the roof angle cf the rrism must te so accurately and finely cut that the roof will reflect ur to the very ridse;otherWise the ridge line will be visible right across tre center cf the image. The edges of the Porro prisne are not used to formu the image. 15.9.Vhich type absorbs the most lizht? Which have the best angle of reflection? A.The Porro rrisms absorb rrobably about 2 o/o more. The reflection in the “rashear-—Fastings prisms is probably somewhat more efficient due to the first and last reflections being at an angle of incidence of 6C degrces instead of 45 uerees. 16.Q.Which type would suffer most from rough handling? A.The Prashear-Fastings. The surfaces cemented together with balsam. may be cracked avcart or the delicate roof angle nicked so that it may become visible,while the central areas of the re- flective surfaces of the Porro rrisms are ro more liable to injury from scratching than are similar areas on the HFrashear Fastings crisms. 144 17.9."hy does 0.4.0.R.537 nrohibit the ta the making cf adjustments other than th descriptive cvanvchlets? king apart of telescopes or is ose described in A.Because of the strong probability of injury to lenses cr prisms from drowning or from scratching and of disturbance of the care ful adjustment of optical natts after test by the makers. It is next to impossible to make nerfect optical parts but it is practical and customary to eliminate the greatest part of the results cf defects by neutralizing one with another,by adjust- ment so that the defect is on the outer edge of the field,and by other devices known to the skilled optician. If his arrange- ment is destroyed,the instrument may ve found almost valueless until readjusted after slow and expensive experimentation. 18.Q.What is meant by the critical angles of prisms? A.The limiting angle of incidence which separates the totally re- flected ray from those which (at least partially) escape into the air-Century Pictionary. The angle of incidence in this case is the same as in Definitione, C.A.D.R.27 and under Plotter,IV Elementary Cunnery,which see. When a light ray strikes the water or nlain class normally (perpendicularly) it passes into the new medium (water or glass As its angle of impact decreases and the angle of incidence increases from zero a smaller and sraller quantity will enter the medium. Wkan all of the light is reflected the critical angle has been reached. Similarly,with the light entering the medium,after traversing it with more or less loss by absorption,the balance strikes the onposite limiting surface. If its angle of incidence is small (cath of ray not far from rervedicular to this second surface) most of the light will escare into the air or medium beyond. A greater and zreater quantity of the light,as the ancle of incidence increases,will be reflected tack thru the mediur inte the air on the sane side as its origin. "hen none passes out into the air on the side opposite its origin,the critical angle his been reached. "Yor glass and water this angle is in the vicinity of 40 degrees. This exnlains tne dazzling sun spots on the water in early morn- ing and late afternoons,also window reflections ao noticeable at these veriods of the aay. 19.Q."hy does the surface of a prism through which you can see, reflect light when in its nlace in a telescope tube? A.Because the surface opposite the point cf entrarce of the ray is so placed as to give an argzle of incidence greater than the critical angle. a” A TPS tion and Neflecticn in a prism" Printer:- Tnsert gketoht! 1 “Ollowineg exnlanation: herewith. haa underne:nt: 7 2 1) cr iad A ray of liznt from tne r trikes the prism at D and 2asses through the rriam to Fh where i reflected in tne directis and finally nazses into the air azain in the direction s F., Tt. is J refracted (cont) at and F seca of the Gizference in density of air and glass. See exnlanation of the princixnle of refraction on page .. It is reflected at F »ecause its ang sla of incidence,)D F C, ig wreater than tne critical angle. The otner lines ard letters indicate an exaet motnod of determining tne vath of tre ray which is too complex for the wursoses of this book, ac .9.Vow many lenses are there in this instrunent? A.Tnree. 21.Q."hat are their names? A.Tne oojective lense which is a om sound lense,the field len ard tre eye lense,tic last two’ ve og simole lenges wo 22.9."hat are their shaves? The naxe ziven to each shane% hd Oo A.Oojective,consisting of a dseuble convex and a sonvexo-concav®; field lenac, rlano convex; eve lense,vlano-cocrvex,. see Figures and —-, snoWing the geveral tyres of lenses. 235.Q.Wwhat is meant by a comnound lense? A.A lense made in two parts held toccther in such a manner that the carts in most resnects act a3 one lense. 24.9.™hat i3s the odject of compounding? A.To neutralize chromatic aberration scrinci ina use this conbination for neutralizing 0%} cvlained under Question 17. nay » Onticians also her acfects as ex- *-25.9."hat is meant by aberration? by achronatic? A.,Averration means wanderin: awvay,hence in this case the wandering away in different directiscnsa of the several colored rays ootained from white light. Achrowatic ~eans wi¢hout color ,for instance a lense from which chromatic aberration ha3 been removed by compounding. See Figure thre2 (3) velow. 46. “isures 1,8,and 3 from article on Ag 30,31, and 33, 7ournal of the t.h. ruary L> 42, Ren numer fivsures in accordance making necessary changes in Figure numoers (Printer: tnsert her Tefects in telescores va Artillery-Canuary and Fe: With numoers in this »d- in text). © + o ») k, Fisure l. A ray of shite light from A striking at 3 is dispersed into tne seven colors; viclet,indics2,bdlue,green,vellow ,orange,and red in tine order naved, vecause tne ray did not strike tre nlate rernendicularly. Figure an The ray 3triking the lenses rerrerdicularly at the point of imract does not suffer color disversion. All other rays are disrnersed as indicated. Each color of ray passing thru the positive lense has a different focus. Tf a ground glass were rlaced any where between Fyand Fa.,an indistinct image having fringes of color around it would be obtained. This is chromatic aberration or color wandering. Note that the positive and negative lenses diperse th colors in opposite directions. Figure 3. This shows the tyne of objective mentioned in Question 22. Note that the eccmpounding of this lense has neutralized the color dispersion of each part. 26.Q.Why are the vcartg of a commound lense senarated? A.Pecause it is not practicable to grind the parts of the lerse so that one will fit the other verfectly. An air bubble between would increase the amount of liffht absorbed, reflected,and othorwise lcst,and would make it easy for dust to collec 3+ between the narts. The snots of contact would loox different than the areas of no contact. Small pieces of naner are used to sevarate the varts and can frequently be seen uron close insvection of an oofective. 27.Q.4ith wh is the snace filled? “hy is this substance used? A.With Canada oalsam decause it transmits light practically as well as ulass and at the same time acts as a hard cement. 28.Q.What deterioration sometines occurs in this substance? Now do you detect it? A.It is not infrejuently found to be cracked after a heavy shock. It then looxs similar to a snalled or split piece of glass but one can usually be distinguished from the other by th whitish or yellow coloring of the balsam. a 1477 22.Q.What does greenish svots on lenses indicate? A.Tre formation of "natina™ on the surface of the lense due to the action of water,the acids in moisture from tne hana, collections of moist dust and oil. 30.Q."hat do brown svots on lenses indicate? A.The decomposition of the lead in the glass,fhese snots are known as lead srots. This occurs on both exterior and in- terior surfaces. 31.0.“hat kind of treatment hasten the development of these snots? A.Failure to kees lenses clean. Tailure touse soft,clean cloths c parer fer cltzaning. Nae of water or saliva ins Handling lenses with tie 2 te an of alchol or eithar,for cleaning. ringers. > * 32.Q.%hat is neant oy the rower of a telescone? the ficld of a telescore? how can you measure each? A.The power cf a lerse is the matic of the diameter of the ooject as seen thru it. The field is measured by the number of dezgrees,ieasuring from the eye of the observer,which tne wnole imaze covers. [It is also exnressed in yards by the extent of the imaze visible at 10CC vards. 33.9."hy is tnere out one wire in this instrument? A.Is surnlied with a vertical wire cnly cecause it is intended only for reading azinuths. No waterlining is necessary. 64.9.4ow is a broken “ire repaired? in an enmersency what material nay be used? A.Maxe a small mark on both the adanter and tuove to aid in secur- ing the correct rositicn in reassemoling. Remove the adanter from the telescone tube. Remove the broken wire. Insert a rew one under tne clamps,winding the ends around the clams and using a dron of shella co to nold the wire nore securely. See that the face of the wirenoluaracross which the wire is stretched is assembled toward tie eve ena. Assemble so that the svring attached to the wire holder is nlaced onnosite the lamp bracket. Tren insert aijusting screws and adjust for correct rosition of collinating wire. In emergency a freshly snun thread from a srider may be used. 35.Q.Who ordinarily replaces oroxen cross wires? A.The resident ordnance machinist. Tnder service conditions how- ever gvun rointers and observers would have to renlace wires for thenselves frequently. SAS 36.9.Wnat does "collimation" inean? Yow do you adjust the tele- spes-e for collimation? Wias is the surnose of thid ad- justient? A.Collimation tweans, the accurate adjustment of the line of Sicht of a telesco-e so that when it is rotated avout its horizontal trunnions the line of sight will remain ina vertical//dxdd olane. Focue and direst the telescone on an object. heverse the tele- scone in its bearings. Traverse the instrument 150 degrees. If it is now on the object, the wire is in collimation. If it i@ not, correct for one half the error by moving tis collimation wire holder and half the error by traversing the telesconve. Reveat until the error is eliminated. 37.Q9%%hy should the »recaution described in questicn 34 be cbhserved when removing the eyexiece auavter? A.Eecause if the wire holder is assencled with the wrens face tc the rear it will ce invecssible to rercve mavallax. ‘and at tre same time ootain a clear inage. 3¢.Q.What is rarallax? A.The change cf rlace cl an objectwher viewed fro: different points. If, wnen looxing through a telescone, the image "dances" on the cross wires when the eve views it from dadiftia - vroints ir the field as a result of movins the neada vack ard forth and ux and dcewn, yvarallax exists. ©°.Q.Ecw is it removed? A.@y focusing tne cojective until tne the inazge is exactly urcr. the crosswires. [f tre image is in front of the crosswires, the ilia-.e moves in the sane uirection as the nead in re- lation to wne crosewires. I? the inage is behind the cross- wires,the movement will ‘ce oprosite Po that of the head,anc will therefore cease when the image and the crosswires coir-. cide. 40.9.Is the reicval cof ~arallax licortant? A.It iA very lincortant since no cgevenuasle results can te Cctair. AIL Loe Prox a telescone until it has ‘seen rei:oved. JLo f fe 43.Q. ne hae %h _inst¥unent uzon a designated point? ct A.Set up he trivcd with cone leg roin: ing in the ,gereral airecuim of the line wrich would bisect the angle throush which it will te necessary to traverse tne instrunent.This will give the minimum of interference of the legs of the trinca with the movenerits cf the observer and will lessen the chances °f his novenents disturoing the setting of the in. StYruient. Screw wae ingtvrunent 70 under aves ston 45 sev Known aZirnwusn of geome ~clrt :o the nearest wiole uepree; turn the 3nod with reacings increasing or uecreasing as the veneral direction of fhe wotion of the Selesuc.e@ ney a/ 4 ty? 2G ne tri-cda Lead; level it as descrivec he index on the rlaten to read the seb tage (9G, a nut fags, 140 Sere. tho instrument to the trinod nead; level it as descrivad under question 4: set the index on +he nlaten to read the azinuth of the known noint to *he wnole degree just short,in the direction of motion,of the exact azimith; turn the xnob so that the motion 2° the index on the nlaten shall »be in the ol same direction as that used for the whole degree setting until the nroner hundredth cf a dezree is obtained; note whether or not index on nlaten now indicates anv roxinataly the azimuth cf the known noint; beine ava end of telesacsone over center of worm box by ’Nclamrine s3loy motion arm clamn,movir the desired amount and again clamning (this to place the window juat to the right of th: aye and of the telescone to facilitate reading aziinaite): gnift the snirndle and all vnarts attearas theret>s on the nare,the levelins screws being loosened for this nursoge,mntil the telerrcre je nointine in the direction of tha known ‘voints level qeratal[w, olvating if neccesary Hv t+he method outlined under yuestions © »nt 7 “-hove; adjust for parallax ana focu3 tne telesocne; dissect the known point coming up from *he same direction of motion of nlaten incex as before; vest dy coming un fron _ tae onnosite direction; Qelininate tue error,itf any, (called » sack lash) as explained under questiors 46 %° dbelow, The imstrasert is row oriented. 43.Q.What is *he advantacse of settines cone ineatrument anrroximately before levelins? A.nlesas the base neo to De exactly varallel to the plane of the level bud les , he shift in azinuthn by moving the levelin= sacra on the tase will comnel relevellins. The initial azimuth gan %2 disturbed for the vnurnod@ge of levelling without materiel disadvantase by simnly turning the worm box eccentric crank to the unclamnad nosition .9.Point out the following narts on the sectional view of the AV etween the svinile und yous vratainine ed azinutr instrument. wo. Part. No. Part. l. Pall and socket joins. B Cun Wasners. 5 Platten (vernier nlate) 4 Disk on svindle head 8. Azimuth clamp shoe. { vraduated lim) o. Worm Gear. 9. Slow motion arm. Yoke retaining Washer. A.Nuncers on s23ction indicate the above varts,number for number. 44.Q.P0int out the vearinz surtices when telescove,voxe and shield revolve around tne sraduated limo. waaher on the one hand L aed and the yoke on the other. 19? The follswine C are to ba inserted after question 4C on rre- » ol ceseding raze. Quastionsa 41 tu ol inclusive suoulda hea renunse: a. e “os - a ~ ” to avree,i.e dl on oreacaaging “are Decvomes Jeo. 41.9.”rat is the fivst adiustvent to “ee inaue on a telescore? Why? A.The adiustnert for rnarallax because :f thea chloective la Too- a fivst it will us vlacna so that iss Leage is correct— ween cs Tv riekad ux bv the eye viece hut in all rnrobapoility the Jetter is roe SOC BAG on the oros? wires. The cress wires will not be in coincidence witn the image of the objective. The cres2 «lre cannot be voved Llonsit Scinally, therefore tie acjustmert for rarallux can only 2@ Hide Ov besinrning over pltr that adiuatyont firet. 42.9.Can yvru reneve all narallax ina two wire instrument the- eretically? Practically? *. Thesreticallyv no,secause the cioss vires have thickness. nen the eve riece 13 aujgratved verfectly. the inage nav be mlaced voon the canter cf either wire tut cannot he rlacea on the center of seth. “rless the Gianeter ct the wire is large when aqjuatnent is hac® uron tua vroint oF esortact of the tuo wires, 20 rearallax «ill net ce neticed excent uncon close inarecticn. a," Ver 45.9.°Toint cut the bearing aurfaces ven telescore ang yYOrne revolve and gsriauated lino and nlaten rérain satstionary:? A,The vcearing 3urface3 are the sane as hefore,excer* that tie rlaten “being stationary, there is mover “ent nebwoon mart of the yoke and the limo in addition. 42.9.Can the levaliny sorev3 be shifted in azinuta? A.Yes. Study above drawing and reread answer to yjuestion 44. 47.9,.When the azimuth acale index indicates an even degree and the hundredths ind@x incic.tes say .17 wnat ia the trouble and now ao vou remedy it? A.The index vointer is cut of adjustment. Loosen the index screw and ahift it the neceaszary anount,first having placed the Nlaten index so that it is set at some even desree mark. 48.Q.uow uo you remove olay or oinding between the worm an. the Worm sear? A.Se.o drawing 22-1-"5,cCvasey Nenression Position Finder Tyne A- I, teneral constriction, %e-tion "hra “orm Box which shows $2 same weonraniam 2s exiats on the azimatn instrument, suoant that it is cavearsed,the nandle being on the left. The worm oox ia vivoted on the richt (left in above view)so hat screwing the worm box adjusting screw in against’a lug, oast as a rart of the Mlaten, vill mush the “ree ena of the worm DOOXx cutWard aiay Trom the worm wheel, This will remove Dinding catweean worm and woris wneel, Screwing the worm oon acjusting scray out allows the worm box srring to crowd to worm into closer contact with the worm wheel. ctr 40.9.How co you remove lonzitucinal play of the worn? A.2y tigntening fhe worm adjus*irs sacrew in the end of the worn 8na 90.Q.Fxplain the action of this screw? A.It draws the siorm shaft shouliler against the worm box shouluer by crowding the index disc against the end of the worms box. 01.9.Wron the index disc fails to 3tay set but revolves until the dise crans 18 down, iat would yeu do? A,Tighten the wor: adjustin: strew. o2.9."hich lamr Licht: the nundrtitha of a dearee sacale? the graduated lim) or azituti circle? A.The save llamo illuninatesboth . Tt ia the one near tne asimuth vindow. IS 2 53.90.How is the vertical wire illuminated’ . - eo 3. , _ A.?y the lany on the riszkt sido of tu2 telescone. Swe apt Lo 14 c ~ Tm -. 54.9.Pamre the prinociral nart3 cf the illuminating cireutsy. vace tre rath of the ourrent thru each rart? A.The azimuth lamo,the vertical wire lanyn,the switch,thea twovay c 4 yah Ray tt + . A OK.) L3sane 29 myer Sutton, Fyze@ oltexK reri3xs$ance a - wety The current having following orde oY snar switen, two way oush button, baens 1 N ’ t9 er tle vertical wire lamr or %n7 azimuth land denendins uron the settinz of the tyvo wav cutton chance “Sack to the 2equre ce ~cuar in the reav2 ge orier,crnitting only the resistanc coil. 55.9.™hat is tre vnurnozs of the teo vay nush button? Ordinarily the cireuit is thri the vartical wir? lano,>ut when it 18 d2eairad +9 reaadi the azimisl. seoaleg, oreavure on the Sutton tip cle32 the cireuit to the suvale lann and ooens the circtuit to the vortices l wire law 98.9.Can the amount of light siven ty the laurs be changed? How?’ Irn noth tamrs ocr only ona? A.Y@s.ihke gsocnxet in the vertical Wire Lamr oratkat has an agjustrent for varyinzg the intensity of illumination -* +).e Wire. Tne azimuth seale lamn socket dses not. o?7.9."nat does svarking in 2a lamn indicnte? A.That the filament (the anall wire insite which slows to vive the lizgtt) is broken. 9&@.9.Fow can you detarmine whether your Laraps are dead,the ocver turned off,or the circuit is broken when “the lanmns fail to glow? A.The rower ts almost a ag yon if other lanmns at the atation are burning. A usual but very safe way is te rlace the fincers across to torninala and "feel" the currant . Thi ous because the line may have been brouczht int a high rotential cirenuit by accident. "nless sti dry clace with dry tn vas a very unson"ortadte shin. exnerienced from a 11C volt circuit. "Inder no cirtuistances should this method ba nun loyed on sixouits known fo rave a higher rotantial. 1 ¢ . ao 1 fae ‘ : ver - - The circuit can be tasted oy mutsing in good new lamrs wien se “ower 13 known to be on. TQ , y +m AH 7 rat y " < “ “4 . ‘ronKen filanent@ car usually ba datected by insnestion in a 50.9 Deecrvibe the mathod of renovying and renlacins lanrs? ATH? lars wctnet Tor the asatnut 1 stale larn oracket ie attachad Dy a bayonet joint Vaaring aljsarsct A wHrinp. ty Nress3ing it inte the Sracanet ana ro itineg 15 to the pets until it bears azaincs tha rain,it may readily %@ reainovead. The vertioril wives Lam “av ba removed ci goervaine the AU jus 5 - ing sleeve to tye richt until *52 soex.et is aseected., The ; roynen Te revliosd. To per lata thia lanv soo%et scren the adiusting sleave until it is abenut Flush vitn toa em oF toe Urisxet anv tna ale in the slaave soincisies with the 31ct in tre Orackatlinsert the eccneat with tha adjusting vin air 35th slote,and rotite the sleeve to the tert, A.Mlosk cil. 1 cino® near yentyallovad for anch instru.oent.7aa C.P.1erS-82, The oil siculd %e atynlied ny droxeninge from the ang oF the dadrovwrear attaonead 419 tea cork. “his vill last ordinarily *ro. Tour to six montha. “reypient cr ans2s3sive Oiling Gill actually (9 narn.,as thea excets asount lll Fle. avay from the “(2arings vo the suarreunuin ard aris - o wpm el 3. AYU So git cC s i ~ bs act r + y + | im og “ye tL - a on V5 to catch dust and ultimately to clov up the 61.9.In vee cor, Wiitien should tne levellin« screws oe left serfere the inetrune is 7 eaturned to the cnest? oO A.tThey should all be Dearing snucly,net too tight,in orcer te prevent the cvinule and unver rarts from "reekine" under the shock of trananortation and handling,te the destruction of the finer adjustments? (Printer: Add here "Names of varts of azimuth instrument®,. vages 7 and 8, and drawing 22 - 1-3 from 0.P,. 1657 - C9) III Fire Control Avparatus. (o)Use of the telenhore. 1.Q9.How wany telephones are there in a standard »attery conmander's, E.C.,atation? To what places do they runt A.Two. One to the fire cormander,™', and one to the observers at the primary,®8!', and at the se ondary,®",stations. 2é/Q.Can the telerhone to ¥' be used for anv other purnose? A No. 3.9.Can the telerhone on the ovoservers'line be used for any cther purnrose? If so what? A.Yes. See diasran of Wiring in 2.C.Station labelled 7.C.STATION STITCHES and note,"“Switches to cut hand set of observers! line in to fire commender's line, and to enable observers' line to b2 uscd as reader«' line in emergercy." 3@ switches,the carts thru which electricity can rass ard tne rositions in Which they are usually set. A.The B.C.STATION SYITCHES are three double pole,double throw Switches, Tne handles and tons are made of hard rubber or otrer nun-conducting material,hence electricity can nass onlv thru the »rass3 “nosts or coles,and from one post to anot-- her on the Drass blade correctiny tyvo posts when the switen is closed.""he middle terminals of the ton switch are conneci «= ed to the ?.C.hand set and the switch is normally open. Fv closing the switch to right,the E.C.hand set is thrown on tc the observers'line. =y closing the switch to left,the F.C. hand set is thrown on to the fire commander's line. ‘he tiadle and bottom switches are normally closeu to the left,ir. which case the @!' and EB" readers are connected to their reay- ective arm seiters in the plotting room (Nos.é and 3 when TUE PACW LINK SYLITCH EOX is set for VORIZOYTAL RACK AVatTE, 5.9.What comoinations are rosaible and what pnurnose does each serve? A.The following comoinaticns are nogssible with these switches:- 1.“hen RASE LINFT STTTCU BOX is set for VORIZONTAL BATE SVSTREY. (a)Middle switch closed to right and »ottom switeh to left.No.3 plotting rocm detail is connected to RB" reader.Nc.2 plotting room a@o*2i1 is connected to R' and EB" obssrver in narallel. This is useful in case cf casualty to 3'reader's line. (o)Niddle switch to left and bottom switch to richt.Mo.8 plotting room aetail is connected to 7! reader.No.3 photting room detail is connected to 3B! and B" onservers in narallel. This ip uectul in case or casualty to #" reader's line. re oO” Aa "os.c and 3 (c)Mide e,and bottom svitgneg cotg,closed to y 3. agetail 3'an na all connectcd Yi nz room 2" opservers ai in Oe arate 1 This is reefeL in case of casualty to both 8! and B" readers lines. “hen sed Nos . 6 and 3 will hear talx from both =! “ht Cc HO, and =" and must select their data. (2)™hen FAST LIVE svTray 2.v jig get for WETICAL TACR OvaTr | ATCPRAVAT TAN TRO BI, In this case the hotton switch of =.C. switches is diso eated from the wlotting roon. 1 (a)MNiddle switch cto:2d to tre left. This connects 2' reader to ‘os. Poona A wIetting room detail in narallel. Thi. is the normal mosition. (b)Middle switch closed to the right. This connects Nos. and 3 rlotting room detail, B’ and 38" obeerver3 all in parallel. This i838 useful in ecrse of casualty to ©! reacers line. (3)When tase line switch box is set for vertical base systen, coservations fron 2". In this resition the riddle switch of *.C.switches ia disconnected from the plotting room, ee (a)Bottom switch closed to left. This connects ™" reader to Mos. 2 ana 38 rlotting room datail in varallel. This is the norral nosition. wy (o)E ‘cttom switch clesed to richt. This connects Fos.2 and 3 plotting room detail,?' ara ™" onservers all in narallel. Thig ic used in ca ase nF casualty tc 1" reacers line. (4)“hen both switches in 2ASkh LINR ewr™ey TAX are closed tc left The connections area “the gine as for 1 avove with "03.8 ard 3 nlotting room detail intorcanged. The switch sheuld ret be used in this nosition. Cc TRHLEPHONE SERVICE, 6 .Q.How would you proceed by practical test to select operators? A.The men should be tested as to their ability to distinguish sounds in a telephone. The following method is suggested: Enunciate distinctly through the telephone letters which sound somewhat alike,as 3,0,?,T,E,and ascertain whether they can be distinguished readily; enunciaté a number of words begin- ning with 5,such as seven,six, sight, sound; try such words as four ,more score, door, bore.C.A.N. R738, After a teat of this kind with an instrument in good order,try with an instrument which is not working well.C.A.D.R.789. . After the hearinz test,give a number of selected words to be sent through the telephone to test the operatoy's ability to enunciate distinctly.C.A.D.K.730. 7.Q9."hat habits of s*:ech and voice tones indicate good material for telenhone operators. A.Other qualifications being equal,men should be selected who are in the habit of speaking slowly and distinctly.A man who raises the vitch of his voice when excited should not be selected.Cc.A.D.A.731., 8.9.hat kind of defects in his telewvhone is an operator exnected to correct for himself. A.Operators should have a sufficient knowledge of their instrun- ents to correct minor defects,such as loose or corroded contacts,or bent levers.¢.*%.D.2.732. 9.9Q.Describe the tests made and action taken »bv each onerator when preparing for 3ervice. A.When vrevaring for service the onerators arrange their apparat- us for communicating and raise and lower the hook switch.If this oneration results in a shary click in the receiver,the battery is in working order.If no click is heard,the binding nost to which the head sets are connected should be examined and tightened.If the hook test indicates that there is no Sattery on the line,tne onerator must notify the electrician sergeant.The principal onerator on etch line calls up all tae others on his line arid reports to the chief of his statior. C.A.D.R.733. 10.9.What can you say about the necessity for nrover care of equinment by each overator? UA; Particular stress should ve laid on the imnortance of training each telenhone onerator to take an interest in the instrument used by him.If each onerator takes nrover care of his inatr- ument the efficiency of the svstem is mich enhanced. 1S, a = 11.Q. “hat action should an cverator toke when closing station? A.The talking set should be hung in its proper place at th completion of arill,hoox anrins ‘should be ir rlace,the cords should be clear of nossible interference ,and a rerort should ve nade voromrtly cf any dsfect in te talsxing clrauit. 12.Q."hat things should be done in the general care of telephone ejuircment? A.The nickel nlatWins sheculd kent nolished with chamois; th cornections external to the transritters and receivers sr. be exaninec often for possicle corrosion and a strip of ha surfaced naner drawn hetvieen platinum contacts to insure thei1 cleanliness. Cords should be examined frevsuently for wear tu3at rehind the tixs. ct Ty 7 ® f W.O."ith vhat vert of the instrument rwiust the crerator not tan ver’ A.Tranexitter shells nis ovrerned by the onerator under anv circurstances.°%.A.0.N.” 14.Q.Ucon tze discovery of an indication of treuble beyond his rover to corre:* +o whom does tne orerator resort and wi:ere will this »ersaon be found. AT: oO the electrician sergeant in charse of that neortion of tne equirnent. Flectrician sergeants are given definite stations and vortions of the equipment to ccver curing drills and action. The electrician serceéant's station should ve known to every onrerator. 15.Q.Enimerete the rules to be followed in sending nessaces: A.1l.Speax into the transiitter holding the head in a natural rosition,the licsa atocut an inch from the transmitter. 2.se a moderate tone of voice and sneak slowly and distinctly, being careful not to slur the sords or syllables,but to enurciate clearlv each sound. d.Never shout or raise the yvitch of the voice. 4.5end numerals singly; thus ,4370 is sent four,three,seven,zero. Never use the letter 9 for zero. In sending an azimuth or anv nom@er involving a decimal,the decimal roirt is called point; 2-46.34 is sent two,four,six,roint,three,four. An exact hundred is sent as a hunured;thus 200 is sent as two hundred,45CC is sent forty-five hundred, The same svstem annlies to sendinxz um exact thousarnd;40CO is sent four thousand. o.if it is necessary to rereat,use more care as to distirctrese but do not raise tne voice. ‘i single nunder not understceda mar be accentuated oy counting un to it and emrnasizging it. Thu if the figure four is not understonod,say four; one two, three, four. 12.9. murerate the rules to be followed in receiving messages. A.1l.Keep the mind cn the message; a nerson can not receive correctly wren he is thinking of somethirg else. ea.Keep the receiver close to the ear. 3.[o not interrunt the sender unless absolutely necessary. ge 1 Notve:- For catechism cn construction and rurrnose of rarts of telexhone,see Anprendix C, fapt/75. JS ® 1SF OBSOIRViIR IV Observer's test,C.A.D.R. This subject is intended to be a practical test of the candidate at the battery. The following questions probably will not he asked in the examination but are added for the instruction of tne candidate as to the points on which he will be judged by the examining officer during the practical test. l.y.What are the qualifications especially to be desired in an observer! A.Observers are selected on account of tneir special aptitude,and mst understand thoroughly the use of their instruments and have a knowledge of tne ypeneral features of warships in order to be qualified for their auties.C.A.D.n.326. 2eQ.For what is the observer responsible? A.Each observer is redsponsible for the care ana adjustment of his instrument and for the security and police of his station at all times,and reports to the range officer deficiencies,defects,or accidental damages as soon as they are known.C.A.D.R.326 3.Q.what is hig personal equipment? A.With the type installation,1909,each observer at the base end stations wears a head receiver and breast transmitter bridged on a line... (observer's line) to the B.C.station,for the purpose of communicating with this station while he is observing.C.A.D.K.326. In the later installations the head receiver and breast transmitter are +3 combined into a head set. 4.Q.How is the practical test conducted? A.In order to select observers who are to work at the ends of the same horizontal base line,two instruments should be set up as near together as practicable and oriented carefully. she observers,using these instruments,track a moving target. Every fifteen seconds a bell is struck three times or READY,1AKE called,ana the readings of the tx instruments compared.C.a.D.R.327. Note:- Hereafter in drill,subcaliber,and service practice with curs,mortars, and mines a 3Q=second observing interval will be employed. Regulations for the Instruction ana sarcpet Practice of Coast Art'y Troops,19i2, 5.Qehat comparisons of data ure observers required to make frequently in drill,and practice? What is its object? A.Arrangements should be made so that observers may compare frequently the ran es to moving objects as determined by a horizontal base,with the readings of the D.P.#. This comparison should be made during the progress of the observations by calling aloud both results. If the plotting board is not at the primary station,the H.B.range can be sent there py telephone.C,A.D.K.329, SEO Tne object is to teach the observer just what he can accomplish with a carefully adjusted instrument in ranse findine by vertical base. 6.Q. What is the nature and purvose of the month test of observers? Is it Optional or mandatory? A.At least once a month durinc the outdoor season D.P.F.observers shall be tested as to their proficiency at rances within the maximum for heicht of instrumcn? as above describcd. Tne test should be conducted so as to determine the relative ability of various observers to read quickly and accurately ranres to fixed ana moving objects.C.A.D.R.330. It is mandatory. 7TeQaunat are the auties of the reacer? A.!:ach reader reads und transmits tne azimuth or azimuth and rance to the plottine YOON .Vestevenedsddbe S.Qevhat cre tic duties of* each member of the fire control section on reachi.- his station? A.To exavine the instruacn* or other matericl to which hs is assicned,to iake the prescritcd tests and adjustment,and to rcport defects,if any, to his chicf of det: il.See C.a.D.R.333, OVST RAVER, V Characteristic features of the sevoral classes of war ae i ships,general knowledge of local shirning,of channels leadins to the haroor,and of ranges to vromineht fixed objects in the field of fire of the battery. For this subject,see the same subject under Gun Commander ang Cun Pointer XT y pape SI, APPENDIX A. A Instructions for printer: Print the paragranns fromw C.A.LP.u.definitions indicated below. Tre check markgas shown in tne three columns ,indicate to the carnuidate which definitions he will ve required to kno... Print tre paragravns in full as given in G.A.DVA. Add the following paragranhs from C.A.PD.N.: 383 nN = el WY ou 326-356 343-353 355 430-504 528-540 545 553-555 976-577 £17-S20 621-653 659-390 757-77S 732-757 702-515 819-822 2234-828 G45 | 48-849 851-8740 255 €69-373 880 862 SEE 859-916 935-950 69-983 697-1004. ae ee es ee ee ee ee eee eee iw ee APPENDIX.A. Extracts from Prill regulations Ceast Artillery,1909 ou Hi © @| > ~, co! @ ci Ss DEFINITIONS AQ, Cc Ww) iN . e t 4 ee. eee oe ty a 21 Aiming. _ Ce e6 Ammunition. b~ , Ao _| ___.. 64 Angle of departure. ~ ) L: 4 85 Angle of fall. Ply _ eG Angle of impact. -| pe 27 Angle of incidence. —, 7 | 28 Angle of position. | e9 Arron. __ 30 Approaches. _ L | | _ oe Atacsphere board. i 1 AY 33 Axis of gun. tT . | 0 _ _ - 34 Axis of trunnions. a! yt | 35 Azimuth of a noint. 7 _ | 36 Azimuth difference. nae ; , | 57 Azimuth instrument _ | Te ___ 39 Base end station. i _! ___40 Base line. | '41 Banquette. a “a 42 Battery — a | 43 Battery commander. —~ tp] - | ; 44 Battery commander's staticn. | 45 Battery commander's walk. 46 | \ \ 4” 49 1 ee eee 7 -- 50 ol “A \ 52 ~y 3 24 jf 9D ~\ ba ee VIESIN IAT NEN| SEY ENS 3 | ; O58 57 08 y 09 SO 61 62 634 WA INNS 63 64 —— ee eee 5 65 NEALALNE SENS ENE Ly ——- tan, 66 67 68 70 71 72 75 SENT XN VAIN 76 Battery parade. Battle area. Blending Bore. Bore sighting. Bourrelet. Breech. Breech block. Breech mechanism. Breech recess. Breech reenforce. Bursting charge. Caliber of gun. Calibration. Cannon. Canopy. Cap. Capital. Carriage or mount. Carriage fixed. Carriage movable (wheeled mount). Carriage coast(A,BjC.) Case I - Case II - Case III. Charge. Chase. Chief of ammunition section. Clinometer. Clinometer rest. SA®D oe, Aol ke ras 29 ry 78 rl ee | 79 po) c ee 80 |e FT 81 m1 | 30 ele| et 93 a 84 “a 85 i“ 86 — 88 | Ae 89 OP AT 90 — — | 91 -~| ea ee | 914 _ Poo || 92 anal 93 - | pj bo 9 -b-=3 94 ~ | Q5 -le-l2o 1 96 an 97 A pte 98 Al eclpe 39 qe le 100 a ~ 101 pale 102 -_ \ 103 Coast artillery fott. Coast artillery garrison. Coast artillery reserves. Coast artillery suvvorts. Communications. Computer. Corrected range. Corridor. Corridor wall. Counterweight. Crane. Danger svace. Deflection. Deflection board. Deflection recorder. Delivery table. Density of loading. Depression vosition finder. Deviation. Deviation at the target. Deviation absolute. Deviation mean lateral. Deviation mean longitudinal. Deviation range. Directing point. Disnlacement of any point. Drift. 104, Y PS J _____ 1053 106 VE YE Sp ey as v 107 109 110 lll no 112 113 114 TEV ES ERIN ASTI six l yt h ‘ AS HA + Yel 15 116 5 117 J —_—— bes 118 , 119 120 \ Elevation. Emergency condition. Emplacement. Emplacement book. Equalizing pipe. Exterior crest. Exterior slope. Field of fire. Fire area. Fire-control Frie-control material. Names of all fire-control stations pertaining toa gun battery and a fire command,their abbreviati- ons and conventional signs. Firing interval. Fixed light. Forcing cone. From battery. 1204Fuze. 1lé1 oe 128 123 124 1285 126 187 rye UM SY yh WILY 1288 189 ‘ 130 Gallery. Gas check. General defense plan. Groove. Gun Gun gommander. company. differences. displacement. platform. pointer 131 132 ry +4 133 ~ 134 135 | 4 136 Lp AF 137 + | 4 138 139 | 140 1 141 ! ! 142 Pon mn 143 7} pep | 144 _ “a “ 146 ab Lt 14? a7 ri 148 _ Lod 149 pe 150 Ae 151 152 153 154 i * 155 157 - Lr i +> 159 Hoist room. Hoop. Identification of a target. Illuminating licsht. In battery. In commission. Indication of a target. In service. Interior crest. Interior slove. Interior wall. Jacket. Jump angle of. Lands. Laying. Line of departure. Line of direction. Line of impact. Line of shot. Line of sight. Loading platform. Loading position. Loading tray. Location of target. Magazines. Manning patty. Manning table. toy g~ ~~ Meterological message. Muzzle. Muzzle velocity. Observer. Observing interval. Observing station. Obturator. Ogive. Orders of fire. Orientation. Orientation table. Parados. Parade slone. Parapet. Plane of departure. Plane of direction. Plane of sight. Plotter. Plotting board. Plotting room. Pointing Case I, Case II, Case III. Point of fall. Point of impact. Position finder:The horiaontal base system. (2)D.P.F. system. (3)The emergency system. Powder chamber. Powder chute. 192 193 194 195 ) 197 198 199 1994 ¥ 800 5 201 808 203 B04 enn vr B05 1) Ny A a 9 \ VfL 206 207 VU SISSY ) ’ { f vw VEY 808 \ + 3809 810 Powder hoist. Powder hoist well Predicted point. Predicted time. Primary station. Primer. Priming charge. Projectile. Quadrant. Quadrant elevation. Ramp. Range. Range azimuth table. Range board. Range difference. Range finder. Range recorder. B11 212 213 214 215 vee He te ft 4 3h —= _\ 216 217 Range Range Rapid Ready. Officer. setter. fire. Rear slope. Receiving table. Recoil. Recoil cylinder. Reference number. 31g. Reserve table. Restricted fire. Rifling Rimbases. Rotating band. Round. ee4;Roving light. ar. 220 | 338 { me l | 229 Pe a 1 | 330 | 331 Do a | Lor A 232 | {! 233 | — 1 a B54 I _, 236 337 . = -_ 838 po | 239 po) bo . 240 i iT 241 242 t--!| eo 243 tL 244 y 247 salvo. Salvo point. Salvo table. Searchlight area. Searchlivcht range. Secondary station. Serving table. Set foward point. Shell room. Shell tracer. B35 Shot gallery. Shot hoist. Shot hoist well Sight. Sight elevation. Striking angie. Striking velocity. Superior slope. Supplementery station. Swell of the muzzle. Tare. ——— ee ot 248 Target. A 249 Telescopic sight. | oe ___ 850 Throttling bar. un |£— rh 251 T-I bell. oy hak oy =. 252 Time range board. en er | _ 853 Tracking. 854 Trajectory. 255 Travel of projectile. Fhe ae a ie oa Travel of target. Traverse. 8 Traversing indicator. Trial shots. Trolley. of. | 261 Truck platform. 4 | 268 Truck recess. is. 263 Trunnions. | 264 Trunnion band. 1 265 Tube. ee __ 866 Twist of rifling. ees | eer Le _867 Unrestricted fire. = sp: a ___868vVent. 4 k- > 269 Wind component indicator. Ye ! ia _____870 Draw a diagram showing all the angles and planes required in these definitions. Co WV a? J APPENDIX 8, Data for cuns,Mortars,and treir Carriages. without change from Gunne?s Instruction (6 Inch Cun), Avnendix 8. APPENDIX «C. Note for printer: Cony Anvendix © of Cunners'Instruction, adding circuit diagrams as per inclosed wrints in addition to circuir diagram shown in Gunners! Instruction. APPETNIY 4, List of Ordnance Pamvuhlete for Reference. Copy without Arnoendix change from Gunner's Inatruction (4 I Poe , APORNTTY ®, Instructions for Loading Projectiles with Explosive DPD. Copy without change from Cunner's Instruction,(6 Ineh Gun), Acrendix FE. APPHMT TXeFr, “rill for 6-inch “Tun,Tisavnearins Carriacze. Cory without change from Tunner's Inatruction {4 Tnch Acendix F. cur) no oa ) ACVUBENDIX S. Nautical and Naval Definitions. Printer cony list on yazes two and three, Coast Artillery “ar Came by Vajor William Chamoerlaine Coast Artillery Corns, ™.S.A. [7° ~” een Pr otf ge. ad ee ee WOoTS HOR DUL™S OTT otal™s. relescopic Sietts,Moccls of L@S6 MI,1ee7,1898 aid 1e9e kh. at a fortification vrere the facilities «ure few for wkinze t* shop tests,the following metiods are outlincc for whe saitance of the offices contuctin wars rhe test for Sha cquality of ibe sich’ trunnions, the ac.uracy of the elevation arc and ceflecvio: scale,the sensitiveness of the levels,an( the horvbarntal motion of ‘he elif ine Claphracn can be dispense? wilh sL its Telore issue ta 3a LL, ~ if ae Soe bp eet na . ob. en SOrvice Vuve heon VOT Oe fo: BI re uLlrewic.. Sy eure fyom che constructio.. of wre siehc,it is obvious tha% these ruguire.. ats can always bo oltaiacc. a Prachot aut 8 accuvately on a horizontal fun trunnion will aisvcr all tne purposes of an efficicnt sup .crt for *he sicl.t curliuc these tests. Leacst for th: parallelis:n cetween t’.e line of sight at zero ceflecction wid clevat'o:.,and the axis of revolution: est cach sicht incopendentl, by setlins it at zero deflection and elcvetiv.. and le in, it on ¢. marx about 38000 yerds distant,aid revolving the sirt* arout its aXS of revolution. If the line of sirch*. is parallel to th» ax ir of revolutiou the iatervsect’on of *he cross wires Vill renaii exactly on si. no the rod bjs ce 0% the sane dista t wark. If uot deflect ‘sc slidi.~ @iaptriem and elevate or dc pre the telescone uncil the lnutersectiouw of we cross wires rer ts 4d. q Une stant crark. Mote “he er-ors in elevation and cefleciticn. q ss exactly ou tae cis “© error in elevation: or ceflect. « exceces Z&!' the sicht sust tc t ! If ° reer Faste?,. selec’ SiOht which has the riadovua errors as tse stale te sick, 2. tost for paral’ clicn botyve nu che axis of the telescope level and “tr uais of revolution of Us siete Wish all tre sivhts set at o.c true line of sieht for zero deflection and elevation,elevate or depress the _un until the telescophe level reads zero. Revolve t:e sivnt about its axis of revolution thru an anele of atour 5. If chs axis of (o> celescop&e level is purallcl vo the axis of revolution, ths bursle should not leave the center of the level. Lost for the cross level “eine at ric’ l auele. to the axis of revolitie. «! we sieht: Level the cross level cf euch sicht, Lleveve the wis thru an anole about 20° Sen the bub ie shoul? remain staticu ry in cle co tor af the cross 1 4, rest for the cross level boiny at rich. ascles co the vertical erc: Tey On a cdistany mark with the sictht set at zero deflection and elevition. Blevace the gun thru an engle of about 15°. Now dcpress the belcscope wutid the intersectica of t's cross wires cuts the point aiveda ut. If it cocs not do so the level is not at right ancvles to *the arc,and the arc is no. vortical. select the sicthts that have fulfilled tho precedin- tests saticfactorily aud set each one ut Lo elevation aud zero Coflection,and lav each one carefull: on a Cistunt merke Cw ° 3 lew Le is’its should 29 interchuceable to within L',and this test walt verify all the precedius tests except 2, If the sirhts show a disaereement in elevation which can no* be accounted for in the preceding tests, thon eet each sisht at *he zero elevation,aud if the dis greene: t still holcs,i due to te trunnions not beine of the sane Cliaceter end the trunnricens mis pave been injurcd., /7P After a sicht has been in use for some time the micrometer of the elevatins worm may be founc not to arree with the vernier. shis is due to a slig¢nt wear of the worm rack,and when the vernier: and micrometer are made to agree at zero,it will sometimes be founce tha., owins to uneven wearins of the rack,they canno* be made to agree at other angles of clevation. When the difference is considerable the sight should be provided with a new rack. Paces v2-13,0.P.1952-03. 3 inch :elescopic Sight model of 1904 and 8 inch Telescopic Sight model of 1yCo. shese sights require none of the above tests. they have no levels nor trunniong axes to test. hey are so cénstructed that the horizontal and vertical axes,about which they move in elevation and azimuth, are ricid with the carriacse. shese axes are by construction properly adjusted and will remain so until wear or injury alters them. © ere ia A | | - J i¢ "7 -_- i ’ er +> = . Sn ws - rm os. 2 : 4: © nN nn gk ne | j f ion \ KR | [= | i ; i + : | t | = = | — = | | ' ' / } i Gun Commander and Gun Pointer, (b) The Telescopic Sight. r uj DD } jf 4 / 4 & 2/2 Y)) Of d EYE PMECE J J / 7 j j - 9? a wy) d } AIR TEM€ geen | Ms a - R ij, j a \ sy fj : fi / HAHA €7 ; ; ; } j ; } ; > < < : 73 J 4 x j j G ‘ a < . ; ‘ YA | a Jit fj) A 4 j i is bien al Terria Lrawlng @ia ? FaLIlhTG /