EXAMINATION FOR TORPEDO-COMPANY GUNNERS.

THE ANEMOMETER.Fig. 73.

THE ANEMOMETER.

Fig. 73.

Q. How are the components of the wind in the direction of the line of fire and in a lateral direction determined? (See Fig. 74.)

A. First: Set the arrow on the disc to read the azimuth of the wind. (This is done automatically.)

Second: Set the little lever-arm at the azimuth of the line of fire.

Third: At the point on the lever-arm reading the velocity ofthe wind as determined by the anemometer, run the finger or a pencil along the nearest line toward the arrow, and where this line cuts the arrow is read the longitudinal component or the component in the direction of the line of fire.

Fig. 74.

Q. How are the wind components determined by the "new method"?

A. 1otarget-pointerto velocity of wind on target-arm.2oSetringto azimuth of wind.3oSettarget-armto azimuth of gun.4oComponents are now read on the dial from the point indicatedby thetarget-pointer. (See Fig. 75.)

WIND COMPONENT. (New Method.)Fig. 75.

WIND COMPONENT. (New Method.)

Fig. 75.

THE AEROSCOPE.Fig. 76.

THE AEROSCOPE.

Fig. 76.

DIFFERENCE CHARTfor10 in. B.L.R. No.1in Battery __________, Fort __________Directing Gun of that Battery10 in. B.L.R. No.2Azimuth of Gun No.1 from DirectingGun, 79°03'Gun Displacement, 38 Yards.Fig. 77.

DIFFERENCE CHARTfor10 in. B.L.R. No.1in Battery __________, Fort __________Directing Gun of that Battery10 in. B.L.R. No.2Azimuth of Gun No.1 from DirectingGun, 79°03'Gun Displacement, 38 Yards.

Fig. 77.

Fourth: From this same point on the little lever-arm run a pencil along the nearest line parallel to the arrow, and where it intersects the diameter of the disc perpendicular to the arrow is read the component in the direction of deflection or the lateral component.

Q. What is a difference chart?

A. One that determines the differences in azimuth and range between the directing-gun and the gun for which it is constructed. It consists of a board having drawn on it circles of different diameters, which are the azimuth difference circles (the amounts being written on each circle). (See Fig. 77.)

Q. How is it used?

A. First: Set the range-arm on the given azimuth.

Second: Run the finger to the given range on the range-arm.

Third: The azimuth difference is read on the nearest circle that cuts the point where the finger last rests, and the range difference is read on the scale in red ink along the azimuth circle of the board. (See Fig. 77.)

Q. What is meant by muzzle velocity?

A. The number of feet per second a projectile is moving at the time it leaves the muzzle of the gun. It is also called Initial Velocity.

Q. From the following gun commanders' range-scale find the time of flight, sight elevation, and quadrant elevation for 4120 yards range.

Gun Commanders' Range-scale.I. V. 2200. 8-inch B. L. R. Smokeless powder.

Quadrant Elevation.RangeSight Elevation.Time of Flight,Degrees.Minutes.Degrees.Minutes.Seconds.+4164100-136-1/5+4184120-11+4204140-058+4234160-0567-2/5+4264180-054+4284200-051+4314220-0498-2/5

ELECTRICAL DEVICE FOR OPERATING ANEMOMETER STOP-WATCH.Fig. 78.

ELECTRICAL DEVICE FOR OPERATING ANEMOMETER STOP-WATCH.

Fig. 78.

A. 6-1/5 seconds, about; 1° 1' minus (depression); 4° 18' plus (elevation).

Q. Describe the atmosphere-board.

A. This is merely a graphic table by means of which the reference-numbers to be recorded on the atmosphere-aeroscope indicator can be determined from the readings of the barometer and thermometer. The arguments are barometer and thermometer readings, and the reference-numbers are indicated by diagonal lines. The thermometer axis is horizontal and the barometer axis is vertical. To increase the ease and rapidity of reading the barometer scale is graduated on a movable T square.

The method of construction is shown in Fig. 79.

Operation.—Set the T square for the thermometer reading and note the diagonal line which intersects the fiducial edge of the T square the nearest to the barometer reading. The atmosphere dial is graduated to ½ per cent. The reading of the board should be taken to the nearest half reference-number.

ATMOSPHERE BOARDFig. 79.

ATMOSPHERE BOARD

Fig. 79.

Q. Point to the following parts of the Mortar Gun-arm:

Movable gun-arm.Yards range.Overlap.Elevations.Time of flight.Zones.

A. See Fig. 80.

Q. Describe the set-forward ruler and explain its use.

A. First find the travel in yards per minute. Set the pointer (a) on the slide (b) at the number of yards on the scale of "yards travel per minute (c)." Then on gun-arm get time of flight for that point. The "set-forward point" will be the reading opposite time of flight on the scale of "yards travel during time of flight +1 minute (d)." (See Fig. 81.)

Example.—After taking four observations on a target we find that in one minute's time it has traveled 200 yards. Set the pointer (a) at 200 yards on the scale (c). On the gun-arm we see that the time of flight for this point is sixty seconds. Therefore our set-forward point is 400 yards, as this is the reading exactly opposite the time of flight on scale (d). (See Fig. 81.)

Q. Describe and explain the use of the prediction scale.

A. The prediction scale is graduated in the same manner as the gun-arm (1" = 300 yards), and is used for finding thepredicted point. After having marked four points on the board, showing the course of the target, place the prediction scale so that zero (0) is on the last point, or reading, and then mark off as many yards in advance of the last point as the first reads from zero. This point is known as the predicted point, and is used by the range officer only. As soon as the predicted point is found he sets his azimuth instrument at the given azimuth and when the target crosses the vertical wire in the instrument, he gives the signal "Fire." (See Fig. 82.)

GUN ARM FOR MORTARS.Fig. 80.

GUN ARM FOR MORTARS.

Fig. 80.

Fig. 81.THE SET FORWARD RULER FOR MORTARS.

Fig. 81.

THE SET FORWARD RULER FOR MORTARS.

Fig. 82.THE PREDICTION SCALE.

Fig. 82.

THE PREDICTION SCALE.

Q. Describe the deflection scale and explain its use.

A. The deflection scale is used to determine azimuth corrections for mortars. After the "set-forward point" has been obtained, the plotter sets the gun-arm on it and by means of theindicatordetermines the zone, range, and elevation of the target. The operator reads the straight azimuth from the gun-azimuth scale and gets the zone and elevation from the plotter. He then sets the elevation scale-pointer at the given elevation, turns crank moving small azimuth pointer to the azimuth he obtained from gun-arm scale; then by referring to the large azimuth scale-pointer he reads the corrected gun-azimuth, which he sends to the pits together with zone and elevation. Should it become necessary to make a correction for drift, turn the deflection-scale knob, either to right or left, as the case may be, as 3 = normal. (See Fig. 83.)

Note.—This apparatus depends upon the fact that the drift is the same for the same elevation in every zone except the eighth. In this zone the instrument cannot be used as now constructed.

Q. State the general appearance, average length, beam, draft, speed, tonnage, thickness of belt and deck armor of battleships, armored cruisers, protected cruisers, torpedo-boat destroyers, and torpedo boats.

A. See Table "A."

Q. Point from Figs. 84 and 85 the following:

Sloop.Schooner.Ship.Bark.Barkentine.Brig.Brigantine.Steam yacht.Revenue cutter.Gunboat.Protected cruiser.Armored cruiser.Battleship.Torpedo-boat destroyer.Torpedo boat.Submarine.Monitor.

Fig. 83.THE MORTAR DEFLECTION SCALE.

Fig. 83.

THE MORTAR DEFLECTION SCALE.

TABLE A.--TABLE OF WARSHIP CHARACTERISTICS.

Characteristics.Battleships.ArmoredCruisers.Large, massiveHigh freeboard,appearance,finelow freeboard,lines, fairlyGeneral Appearance.large, turrets,heavy gunsheavyand turrets,guns, heavygreatarmor,length asmoderatecomparedspeed.to beam,high speed.Average length400 feet500 feetAverage beam75 feet67 feetAverage draft29 feet28 feetAverage speed17 knots21 knotsAverage tonnage15,000 tons11,000 tonsAver. thickness, belt armor13 inches5 inchesAver. thickness, deck armor3 inches3-1/3 inchesTorpedoCharacteristics.ProtectedBoatTorpedoCruisers.Destroyers.Boats.High freeboard,Very long,Small size,moderatenarrowlong,size, verybeam,narrow,General Appearance.fine lines,highnot aslight armament,bow, lowmanynarrowfreeboard,smokestacksbeam.manyas asmokestacks.destroyer.Average length350 feet250 feet175 feetAverage beam50 feetAverage draft22 feetAverage speed22 knots31 knots28 knotsAverage tonnage5000 tons350 tons200 tonsAver. thickness, belt armornoneAver. thickness, deck armorProtectivedeck 2 ins

Q. What vessels are unarmored?

A. Gunboats, torpedo-boats and destroyers.

Q. What is the best part of a ship to attack at long range?

A. The decks.

Q. What part should rapid-fire guns attack at short range?

A. Sides, ends, and small turrets, and guns protected only with shields. These rules, however, may vary with height of battery, form of attack, and class of ships attacking.

Q. How are ships of the U. S. Navy distinguished, knowing their names? (See Fig. 86.)

A. Battle-ships are generally named after States (except the Kearsarge), cruisers after large cities, gunboats after historical cities as a rule, coast-defense monitors have Indian names, torpedo-boats and torpedo-boat destroyers are named after heroes of wars. (The above rules have a few exceptions.)

Q. From the silhouettes on Fig. 86, Ships of the U. S. Navy, find a battle-ship, a high-speed cruiser, a gunboat, a coast-defense monitor.

Fig. 84.

Fig. 85.

Fig. 86.

SignalNumber. Name.1 Katahdin2 Wilmington (2B Helena)3 Terror4 Amphitrite5 Miantonomoh6 Monterey7 Puritan8 Monadnock9 Vesuvius10 Buffalo11 Castine (11B Machias)12 Marietta (12B Wheeling)13 Bancroft14 Bennington (14B Concord, 14C Yorktown)15 Isla de Cuba (15B Isla de Luzon)16 Texas17 Annapolis (17B Newport, 17C Princeton, 17D Vicksburg)18 Dolphin19 Petrel (19B Don Juan d'Austria)20 Alabama (20B Illinois, 20C Wisconsin)21 Iowa22 Indiana (22B Massachusetts, 22C Oregon)23 Nashville24 Chattanooga (24B Cleveland, 24C Denver, 24D Des Moines,24F Galveston, 24G Tacoma)25 Marblehead (25B Detroit, 25C Montgomery)26 Philadelphia27 Minneapolis28 Raleigh30 Chicago31 Newark (31B San Francisco)32 Atlanta (32B Boston)33 Kearsarge (33B Kentucky)34 Baltimore35 Albany36 New Orleans37 New York38 Brooklyn39 Columbia

A. Signal numbers 20, 30, 23, 6.

Q. Find from Figs. 86 to 93 inclusive, a battle-ship, cruiser, monitor, and gunboat of the navies of Germany, France, England, Japan, and Russia.

Fig. 87.

Q. What thickness of Krupp cemented armor will a six-inch gun penetrate at 5000 yards? An eight-inch gun? A ten-inch gun? A twelve-inch gun, model 1895? A twelve-inch, model 1900?

A. Six-inch penetrates 3 inches; eight-inch, 5 inches; ten-inch, 7 inches; twelve-inch '95, 10 inches; twelve-inch 1900, 12 inches. (See Armor-attack Sheet, Fig. 87.)

SILHOUETTES OF SHIPS OF RUSSIAN NAVY.Fig. 88.

SILHOUETTES OF SHIPS OF RUSSIAN NAVY.

Fig. 88.

Signal Name.Number.1 Khrabry2 Grosiastchy (2B Otvajny, 2C Gremiastchy)3 Abrek4 Possadnik class5 Bobr6 Giliak7 Peter Veliky8 Nachimoff9 Spiridoff (9B Greig, 9C Lazareff, 9D Tchitchagoff)10 Mandjur (10B Tchernomoretz, 10C Zapororozets, 10D Donetz)11 Koreitz12 Koubanetz (12B Uraletz, 12C Teretz)13 Pamiat Merkuria (Euxine)14 Strelok (class in order named)15 Ekaterina II (15B Tchesma) (Euxine)16 Sinop (16B Georgi Pobiedonosetz) (Euxine)17 Lieut. Ilyin (Euxine)18 Kapitän Saken (Euxine)19 Dvenadsat Apostolof (Euxine)20 Sissoi Veliky21 Rostislav (Euxine)22 Tri Svititelia (22B K. P. Tavritchesky) (Euxine)23 Apraksin (23B Oushakoff, 23C Senyavin)24 Poltava (24b Petropavlovsk, 24C Sevastopol)25 Alexander II (25B Nikolai I)26 Rynda (26B G. Edinburgski, 26C General Admiral, 26D Minin)27 Rurik28 Viestnik class29 Korniloff30 Vladimir Monomakh31 Dmitri Donskoi32 Navarin (twin funnels)33 Svietiana34 Bogatyr35 Pallada (35B Aurora, 35C Diana)36 Novik37 Peresviet (37B Osliabia)38 Pobieda39 Retvisan41 Variag42 Bayan43 Gromovoi (43B Rossia)44 AskoldNote.—Some of these ships have been destroyed by the Japanese.

SILHOUETTES OF SHIPS OF GERMAN NAVY.Fig. 89.

SILHOUETTES OF SHIPS OF GERMAN NAVY.

Fig. 89.

Signal Name.Number.1 Bieneclass2 Bremse (2B Brummer)3 Jagd (3B Wacht)4 Siegfriedclass5 Odin6 Baiern (6B Baden, 6C Sachsen, 6D Würtemburg)7 Hela8 See Adlerclass9 Geier10 Buzzard, Falke, etc.11 Meteor (11B Comet)12 Oldenburg13 Jaguaur (13B Iltis)14 Tiger (14B Luchs)15 Blitz (15B Pfeil)16 Gazelle (16B Nymphe, 16C Niobe, 14D Ariadne, 16F Medusa,16G Thetis, 16H Niobe)17 Hagen (and others as reconstructed)18 Aegir19 Irene (19B Prinzess Wilhelm)20 Kaiser Friedrich III21 Kaiser Wilhelm II (21B K. Wilhelm der Grosse, 21C Barbarossa,21D Karl der Grosse)21f Wittelsbachclass22 Fürst Bismark22b Prinz Heinrich23 Brandenburg (23B Worth, 23c Weissembourg,23D K. Friedrich Wilhelm)24 Deutschland25 Kaiser (25B K. Wilhelm)26 Greif27 Gefion28 K. Augusta29 Hertha (29B Hansa, 29C Vineta, 29D Freya, 29F Victoria Luise)

SILHOUETTES OF SHIPS OF FRENCH NAVY.Fig. 90.

SILHOUETTES OF SHIPS OF FRENCH NAVY.

Fig. 90.

Fig. 91.

Signal Name.Number.1 Onandaga2 Acheron (2B Cocyte, 2C Phlegeton, 2D Styx)3 Flamme (3b Grenade)4 Tonnant5 Tréhouart6 Tempête (6B Vengeur)7 Fulminant8 Tonnere9 Furieux10 Dragonne11 Leger (11B Levrier)12 Fusée (12B Mitraille)13 Magenta14 Formidable15 Vauban16 Duguesclin17 Friedland18 Baudin19 Marceau20 Neptune21 Redoutable22 Bombe (22B Coulverine, 22C Dague, 22D Fleche,22F S. Barbe, 22G Lance, 22H Salve)23 Wattignies (23B Fleurus, 23C Epervier, 23D Condor, 23F Vautour;some of these liable to be without main mast)24 Terrible (Requin transformé probably 24B)25 Indomptable26 Caïman27 Hoche28 Courbet28b Dévastation29 Duperré30 Jémappes (30B Valmy)31 Bouvines32 Dunois33 D'Iberville34 Casablanca (34B Cassini)35 Forbin (35B Coetlogon)36 Sfax37 Jean Bart38 Alger (38B Isly)39 Descartes (39B Pascal)40 Catinat (40B Protet)41 Suchet42 Davout43 Linois44 Galilée (44B Lavoisier)45 Henri IV46 Brennus47 Carnot48 Charlemagne (48B St. Louis, 48C Gaulois)48d Jena49 Masséna50 Bouvet51 Charles Martel52 Charner (52B Chanzy, 52C Bruix, 52D Latouche Tréville)53 Dupuy de Lôme54 Jauréguiberry55 Troude (55B Cosmao, 55C Lalande)56 Milan57 Kersaint58 Surcouf59 D'Estrees (59B Infernet)60 Foudre61 D'Assass (61B Du Chayla, 61C Cassard, 61D Friant,61F Chasseioup Laubat, 61G Bugceud)62 Pothuau63 Tage64 D'Entrecasteaux65 Cecille66 Chateaurenault67 J. de la Gravière68New armoured cruisers69 Guichen70 Jeanne d'Arc

SILHOUETTES OF SHIPS OF JAPANESE NAVY.Fig. 92.

SILHOUETTES OF SHIPS OF JAPANESE NAVY.

Fig. 92.

Signal Name.Number.1 Hei Yen2 Sai Yen3 Matsushima4 Itsukushima (4B Hashidate)5 Tatsuta6 Tsukushi7 Yayeyama8 Maya (8B Atago, 8C Chiokai)9 Akagi10 Naniwa (10B Takachiho)11 Takao12 Fuso13 Toyohaschi14 Oshima15 Hi Yei (15B Kongo) (Kongo has no chart-house)15C (D and F) (Katsuragi class)16 Chiyoda17 Miyako18 Chihaya19 Akashi20 Yoshino21 Takasago22 Kusagi (22B Chitose)23 Suma24 Idzumi25 Akitsushima26 Chin Yen27 Fuji (27B Yashima)28 Asama (28B Tokiwa)29 Asahi29B Mikasa30 3400-ton cruisers31 Azuma32 Yakumo33 Idzumo (33B Iwate)34 Shikishima35 Hatsuse

SILHOUETTES OF SHIPS OF ENGLISH NAVY.Fig. 93.

SILHOUETTES OF SHIPS OF ENGLISH NAVY.

Fig. 93.

Fig. 94.

Fig. 95.

SignalNumber. Name.1 Polyphemus2 Abyssinia (2B Magdala)3 Glatton4 Cyclops (4B Gorgon, 4C Hecate)5 Conqueror (5B Hero)6 Rupert7 Hotspur8 Rattlesnake9 Blonde10 Scout (10A Fearless)11 Mersey (11B Severn, 11C Thames, 11D Forth)12 Brambleclass13 Brisk (13B Mohawk)14 Orion15 Ajax (15B Agamemnon)16 Colossus (16C Edinburgh)17 Cockatrice or Goldfinch class18 Nymphe (18B Buzzard, 18C Daphne, 18D Phoenix)19 Basilisk (19B Beagle)20 Icarusclass(in order named)21 Satelliteclass(in order named)22 Archer (22C Cossack, 22D Tartar, 22F Racoon, 22G Porpoise)23 Iron Dukeclass25 Monarch26 Trafalgar27 Nile28 Sanspareil29 Barracouta (29B Blanche, 29C Barrosa)30 Hood31 Centurion (31B Barfleur)32 Royal Sovereign (32B Empress of India, 32C Resolution, 32D Repulse,32F Ramillies, 32G Revenge, 32H Royal Oak)33 Renown34 Majestic (34B Magnificent, 34C Mars, 34D Prince George, 34F Jupiter,34G Illustrious, 34H Victorious)35 Hannibal (35B Cæsar)36 Imperieuse (36B Warspite)37 Dreadnought (37B Devastation, 37C Thunderer)38 Collingwood39 Benbow40 Rodney41 Camperdown (41B Anson, 41C Howe)42 Vulcan43 Pallas (43B Pearl, 43C Philomel, 43D Phœbe44 Melpomene45 Apollo class (B, C, D, F, G, H, J, K, L, M, N, P, Q, R, S, T, V, X, Z)46 Hermione class (46B Astræa, C, D, F, G, H, K)47 Hawke (47B Edger, 47C Endymion, 47D Grafton, 47F Theseus,47G St. George, 47H Gibraltar)48 Crescent (48B Royal Arthur)49 Sharpshooter50 Seagull51 Assayeclass52 Alarmclass53 Dryadclass54 Grasshopper (54B Spider)55 Sandfly56 Talbot57 Pelorusclass58 Katoombaclass59 Marathon (59B Magicienne)60 Medea (60B Medusa)61 Temeraire62 Blake (62B Blenheim)64 Minerva (64B Diana, 64C Venus, 64D Juno, 64F Doris, 64G Eclipse,64H Dido, 64J Isis)65 Neptune66 Inflexible (rig shown is not yet fitted)67 Canopus (67B Goliath, 67C Ocean, 67D Glory, 67F Albion,67G Vengeance)68 Formidable (68B Implacable, 68C Irresistible, 68D London,68F Bulwark, 68G Venerable)69 Hercules70 Sultan71 Iris72 Arethusa (72B Amphion)73 Mercury74 Leander (74B Phæton)75 Alexandra76 Superb77 Barham (77B Bellona)80 Speedy81 Arrogant (81B Furious, 81C Gladiator, 81D Vindictive)82 Hermes (82B Highflyer, 82C Hyacinth)86 Diadem (86B Europa, 86C Niobe, 86D Andromeda, 86H Spartiate,86J Amphitrite)87 Ariadne (87B Argonaut, 87C Spartiate, 87D Amphitrite)88 Cressy (88B Aboukir, 88C Hogue, 88D Sutlej, 88F Euryalus,88G Bacchante)90 Powerful (90B Terrible)

CODE FLAGS AND PENNANTSINTERNATIONAL CODE OF SIGNALSU.S. STORM SIGNALSFlags 8 feet square. Pennants 5 feet hoist, 12 feet flyU.S. WEATHER-BUREAU SIGNALSFig. 96.[To face page 168.]

CODE FLAGS AND PENNANTS

INTERNATIONAL CODE OF SIGNALS

U.S. STORM SIGNALS

Flags 8 feet square. Pennants 5 feet hoist, 12 feet fly

U.S. WEATHER-BUREAU SIGNALS

Fig. 96.

[To face page 168.]

EXPLOSION OF A SUBMARINE MINE BY THE GUNNERS OF THE 54TH CO. C. A., FORT TOTTEN, N. Y.(Observation Firing on a Miniature Battleship used as a Target.)[To face page 169.]

EXPLOSION OF A SUBMARINE MINE BY THE GUNNERS OF THE 54TH CO. C. A., FORT TOTTEN, N. Y.

(Observation Firing on a Miniature Battleship used as a Target.)

[To face page 169.]

Ammunition, Nomenclature, and Service of Piece.

Note.—In the following series of questions and answers the new and adopted system only is included.

Q. What guns are usually assigned to torpedo companies?

A. R. F. guns, principally 3-inch.

Q. Give a rough outline of the general operation of the system of submarine mines.

A. A submarine mine is a ball-shaped iron case filled with high explosive. Several of these areplantedacross a channel and held below the surface of the water by heavy anchors. From each mine is run a single-core cable. All these cables join the wires of a multiple-core cable which runs to the "mining casemate." In this building are electrical devices for firing the mine either when it is struck by the enemy's ship (called "contact-firing,") or at the mine-commander's will ("observation-firing"). This firing is accomplished by sending an electric current through the cable to the mine. Inside the mine is an electric fuse. The return-circuit is by ground. (The details of electrical and engineering features and wiring are not required of a second-class gunner.)

Q. What ammunition is used in the 3-inch R. F. gun?

A. A cartridge case of solid drawn brass about 23 inches long containing a powder charge in the base of 5 pounds of smokeless and a projectile weighing 15 pounds in the top. Armor-piercing shell and shrapnel are also used. The saluting charge weight, 2 pounds.

Q. What primer is used?

A. The Frankford Arsenal 110-grain igniting. (See No. 2, Fig. 97.)

Q. Name the principal parts of this primer.

Fig. 97.IGNITING PRIMERS FOR R.F. GUNSNO. 1 IGNITING PRIMER FOR FIXED AMMUNITIONNO. 2 10 GRAIN IGNITING PRIMERNO. 3 20 GRAIN IGNITING PRIMER

Fig. 97.

IGNITING PRIMERS FOR R.F. GUNS

NO. 1 IGNITING PRIMER FOR FIXED AMMUNITION

NO. 2 10 GRAIN IGNITING PRIMER

NO. 3 20 GRAIN IGNITING PRIMER

A. Body, obturating-cup, vent-closing disc, primer charge, end-closing wad. (See No. 2, Fig. 97.)

Note.—The following data is given for general information only:

Weight of the piece, 1722 pounds. Length, 154·5 inches. Length of bore, 50 calibers. Number of grooves, 24. Twist of rifling, 1 in 50 calibers at the breech and increasing to 1 in 25 at the muzzle. Kind of powder, smokeless. Weight of charge, 5 pounds. Weight of projectile, 15 pounds. Muzzle velocity, 2600 feet per second. Muzzle energy, 702·9 foot-tons. Penetration in steel, at the muzzle 5·37 inches; at 1000 yards, 3·82 inches; at 2000 yards, 2·72 inches; at 3000 yards, 1·94 inches.

Q. Point out the following parts of the breech-block:

Block.Carrier plate.Carrier plate ring.Locking spring.Lever handle.Threaded sectors.Slotted sectors.Extractor.Firing pin.

A. See Figs. 17 and 19.

Q. What acts as the gas check?

Q. How should a 3-inch R. F. breech-block be cared for—kind of oil, etc.

A. Same as for any other heavy gun. (See first part of book.)

Q. Describe how the extractor and firing pin work.

A. (This will have to be done at the gun.)

Q. Describe the action of the lever handle.

A. (Do this at the gun.)

Q. Point out the following parts of the gun and mount (masking parapet mount):

Outer base.Inner base.Counterweights.Recoil-cylinder.Piston-rod.Pivot.Pivot yoke.Trunnions.Traversing clamp.Elevating clamp.Range drum.Cradle.Elevating gear.Sight.Night Sights.Ratchet lever.Lever pawl.Ratchet-wheel pawl.Pivot socket and clamp.Shield.Muzzle.Breech.Bore.Chamber.

A. See Figs. 17 and 19.

Q. How are rapid-fire guns cared for and kept in working order?

A. Same as the 12", 10", 8", 6", etc. (Given under heading for second-class gunners, Gun-companies.)

Q. How many men constitute a gun detachment for the 3-inch R. F. gun (masking parapet mount) and give the posts of each?

A. Chief of detachment, gun-pointer, and 5 men.

Chief of detachment, 2 yards to the right of the carriage, facing it.Gun-pointer, immediately in rear of the shoulder piece, facing to the front.No. 1, 2 feet to the right and rear of the breech facing it.No. 2, 2 feet to the left and rear of the breech facing it.No. 3, on the right of the gun, near the elevating clamp, facing to the front.No. 4, 3 feet in rear of the breech facing it.No. 5, near the ammunition recess, facing the gun.

Chief of detachment, 2 yards to the right of the carriage, facing it.

Gun-pointer, immediately in rear of the shoulder piece, facing to the front.

No. 1, 2 feet to the right and rear of the breech facing it.

No. 2, 2 feet to the left and rear of the breech facing it.

No. 3, on the right of the gun, near the elevating clamp, facing to the front.

No. 4, 3 feet in rear of the breech facing it.

No. 5, near the ammunition recess, facing the gun.

The posts of the gun detachment as given above are for inspection and preparatory to the service of the gun.

The men resume their posts on the completion of any duty requiring them elsewhere.

The chief of detachment and gun-pointer go wherever their presence is necessary.

Q. Give the duties of the gun commander, chief of detachment, and gun-pointer.

A.The gun commanderindicates the target, repeats the commands "Commence firing" and "Cease firing," announces thekind of projectile to be used, the order of fire, and, in restricted fire, the number of shots and the firing interval. He is responsible to the battery commander for the condition of the material and the efficiency of the personnel of his command, sees that the guns, magazines, equipments, and implements are properly secured after the day's drill.

The chief of detachmentis responsible that the gunner identifies the target. He is particularly charged with seeing that his piece is properly loaded and that the precautions for safety in case of misfires are carried out. At the command "Cease firing" he will cause the breech to be opened.

The gun-pointeris responsible for the proper regulation of the current for the lights of the night sights. He adjusts the sight in its seat and sets the elevation and the deflection scales for the indicated range and deflection. He aims the gun and fires as soon after the command "Ready" as the piece is aimed. He will observe the splash of his shots if possible and when necessary make the proper correction on his sight. In connection with the gun commander he determines the deflection correction for travel of target, using the deflection scale for the purpose.

Q. Give the duties of the members of the detachment for loading and firing.

A.The chief of detachmentindicates the target and range and commands: 1.No. —, 2.With(such projectile), 3.Commence firing(or, so many rounds,commence firing).

He repeats the commandcease firing.

After the first round the projectile is named only when a different kind is ordered and the gun is loaded without command immediately after it is fired.

The gun-pointer, when the gun has the proper elevation, commands and signalsclamp. He fires by lanyard and in simulated firing calls outfirewhen he pulls the lanyard, as a signal to load.

No. 1opens the breech, closes it as soon as the cartridge is inserted, and calls outreadyas soon as he is clear of the recoil.

(If there is any difficulty in opening or closing the breech, he examines the threads of thebreech-block, wipes off any dirt found, and oils the mechanism.)

No. 2receives a round of ammunition from No. 5 and inserts it in the chamber.

(If there is difficulty in opening or closing the breech, he examines the threads of thebreech recess, wipes off any dirt found, and oils the threads if they become dry.)

No. 3clamps the gun in elevation at the gun-pointer's command and unclamps immediately after the gun is fired.

No. 4receives the empty cartridge case as it is ejected and lays it aside.

No. 5brings a round of ammunition of the designated kind from the recess and passes it to No. 2.

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