Chapter II: Examination of First-Class Gunners (2)

1 Polyphemus
2 Abyssinia (2B Magdala)
3 Glatton
4 Cyclops (4B Gorgon, 4C Hecate)
5 Conqueror (5B Hero)
6 Rupert
7 Hotspur
8 Rattlesnake
9 Blonde
10 Scout (10A Fearless)
11 Mersey (11B Severn, 11C Thames, 11D Forth)
12 Bramble _class_
13 Brisk (13B Mohawk)
14 Orion
15 Ajax (15B Agamemnon)
16 Colossus (16C Edinburgh)
17 Cockatrice or Goldfinch class
18 Nymphe (18B Buzzard, 18C Daphne, 18D Phoenix)
19 Basilisk (19B Beagle)
20 Icarus _class_ (in order named)
21 Satellite _class_ (in order named)
22 Archer (22C Cossack, 22D Tartar, 22F Racoon, 22G Porpoise)
23 Iron Duke _class_
25 Monarch
26 Trafalgar
27 Nile
28 Sanspareil
29 Barracouta (29B Blanche, 29C Barrosa)
30 Hood
31 Centurion (31B Barfleur)
32 Royal Sovereign (32B Empress of India, 32C Resolution,
32D Repulse, 32F Ramillies, 32G Revenge, 32H Royal Oak)
33 Renown
34 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 Collingwood
39 Benbow
40 Rodney
41 Camperdown (41B Anson, 41C Howe)
42 Vulcan
43 Pallas (43B Pearl, 43C Philomel, 43D Phoebe)
44 Melpomene
45 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 Sharpshooter
50 Seagull
51 Assaye _class_
52 Alarm _class_
53 Dryad _class_
54 Grasshopper (54B Spider)
55 Sandfly
56 Talbot
57 Pelorus _class_
58 Katoomba _class_
59 Marathon (59B Magicienne)
60 Medea (60B Medusa)
61 Temeraire
62 Blake (62B Blenheim)
64 Minerva (64B Diana, 64C Venus, 64D Juno, 64F Doris, 64G Eclipse,
64H Dido, 64J Isis)
65 Neptune
66 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 Hercules
70 Sultan
71 Iris
72 Arethusa (72B Amphion)
73 Mercury
74 Leander (74B Phæton)
75 Alexandra
76 Superb
77 Barham (77B Bellona)
80 Speedy
81 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)
]

]

]

EXAMINATION FOR TORPEDO-COMPANY GUNNERS.

SECOND-CLASS GUNNERS.

_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 are _planted_ across 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.

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.

POSTS.
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 commander_ indicates the target, repeats the commands "Commence firing" and "Cease firing," announces the kind 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 detachment_ is 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-pointer_ is 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 detachment_ indicates the target and range and commands: 1. _No_. --, 2. _With_ (such projectile), 3. _Commence firing_ (or, so many rounds, _commence firing_).

He repeats the command _cease 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 signals _clamp_. He fires by lanyard and in simulated firing calls out _fire_ when he pulls the lanyard, as a signal to load.

_No. 1_ opens the breech, closes it as soon as the cartridge is inserted, and calls out _ready_ as soon as he is clear of the recoil.

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

_No. 2_ receives 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 the _breech recess_, wipes off any dirt found, and oils the threads if they become dry.)

_No. 3_ clamps the gun in elevation at the gun-pointer's command and unclamps immediately after the gun is fired.

_No. 4_ receives the empty cartridge case as it is ejected and lays it aside.

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

MATERIAL AND DUTIES OF THE LOADING-ROOM.

(Except electrical principles involved.)

Q. What apparatus is used in making a Turk's head?

A. A navy knife and tool-box "D" is required. Besides the tools the box should be equipped with a supply of Turk's head collars and marline.

Q. What is used in making a telegraph-joint?

A. A pair of pliers, navy knife, and, where insulation is desired, okonite tape.

Q. What is used in making a joint to be used under water?

A. A navy knife, tool-box "D," junction-boxes in which to clamp the Turk's heads, and the material for making okonite joints or the cores. These materials are, okonite tape, cement, Manson tape and tin-foil. A torch is needed for vulcanizing the joint. Brass jointers are sometimes used in making the joints.

Q. Point out all the parts of an assembled mine.

A. See Fig. 98.

Q. Point out the following parts of a compound plug: circuit-closers; transformer; loading-wire; fuse-wires; fuses; fuse-can; bursting-charge; set-screw for fuse-can; lead or graphite gasket for same; rubber packing; brass washers; fuse-can cap; lower tube set-screw; gland; lower tube; plug proper; loading-wire.

Q. Name some of the duties in the loading-room.

A. Loading mines with explosives; assembling them complete to the single-core cable; preparing compound plugs, cables, and raising-ropes; in other words, preparing a mine for planting in the harbor, except attaching the anchor and mooring-rope.

Q. Make a telegraph-joint.

A. See Figs. 99 and 100.

Q. Make a Turk's head.

A. See Fig. 101. Trim the ends square: 15 inches from it place a wrapping of a few turns of marline overlapping each other and secured by a square knot. Slip on the collar, flat side against the stop of the marline; bend the iron wires back over the collar and cut off 4 inches from one and 6 inches from the next, alternately. Bend the wires with the pliers as so to closely fit and crimp the collar. Beginning at the Turk's head, wrap closely with marline so as to bind the wires to the cable. The jute covering and serving maybe bent back over the wires, or it may be cut off: in cutting turn the edge of the knife away from the cable.

Q. Make a taped joint, place it in salt water for 30 minutes and test.

A. 1^o Bare the two ends of wire about ¾ inch.

2^o Join by brass jointer, then crimp.

3^o Cover with rubber cement.

4^o Wrap with tape, about five or six layers.

5^o Wrap with tin-foil.

6^o Wrap with Manson tape.

7^o Vulcanize for about 30 seconds and unwrap tin-foil and Manson
tape and rewrap with new Manson tape.

Q. How is a taped joint vulcanized when in the "distribution-box boat"?

A. By tying a piece of waste soaked in kerosene to a wire lighting, and using this as a torch for heating the joint.

Q. Explain the method of preparing a compound plug.

A. This will have to be learned by practice and constant instruction at the loading-room.

_Note._--The transformer, fuse, can, etc., on the compound plug are still in a state of experimentation and no method for the assembling of the latest design has been adopted as yet.

Q. How do you test the transformer?

A. With a circuit detector or galvanometer and a dry cell, as shown in figure.

_Note._--In case of a break in the coil, Fig. 102, there would be no current flowing in galvanometer and no deflection of the needle would be indicated.

The wires that should show _closed_ circuit are the two red wires and the black wire and transformer case. Those that should be _open_ are the black, and either red wire. (See Fig. 102.)

Q. How are fuses tested?

A. With a dry cell and a circuit detector. A closed-circuit test is all that is necessary. This should always be done under the supervision of an experienced electrician.

Q. What apparatus is used in preparing a compound plug complete?

A. Bench vise, S-wrench, large monkey wrench, screw driver, small pliers, navy knife, loading wire, cotton-braided wire, priming charge, fuses, rubber packings, brass washers, followers, lead washers, set screws, red lead or ruberine, circuit detector, brass jointers, rubber tape.

Q. What is the method of numbering mines?

A. Facing in the direction of the expected approach of the enemy's ships, mines are numbered from left to right, beginning with No. 1.

Q. How are groups numbered?

A. In the same manner. No. 1 group on the left, No. 2 next toward the right, etc.

Q. How are the mooring-ropes prepared, and what are the rules for length of mine cables and of mooring-ropes?

A. The mooring-cables are cut off with square ends and the ends passed through the holes in the mooring-sockets. The strand and wires are untwisted and spread out for a length equal to the length of the socket-hole. The rope is then pulled back until the loose ends are about flush with the top edge of the hole; a piece of marline is tied about the rope below the socket. If necessary to hold the socket a piece of burlap may be wrapped around below the socket and a fold allowed to fall over the hand. Generally means can be found to set the socket upright while pouring full of alloy. Great care must be taken to see that there is no water or surplus oil on the socket or mooring-rope before pouring the alloy. (Nine parts lead, 1 part antimony.)

Mines are planted with a submergence of 5 feet below mean low water.

Where ordinary anchors are used the mooring-ropes must be prepared for depths obtained by sounding. If sockets are used, the ropes for No. 32 cases are but 10 feet less than the ascertained depths at mean low water. This allows 5 feet for submergence and 5 feet for mine, mine bail, sockets, shackles, and anchor. For the larger mine cases an additional allowance must be made for the length of the cylindrical part of the case. Finally each mooring-rope is tagged at each end with the number of the corresponding mine.

Mine cables are cut to the following lengths, plus twice the approximate depth of the water:

Feet.

No. 1 1425
No. 2 1225
No. 3 1025
No. 4 825
No. 5 725
No. 6 625
No. 7 525
No. 8 475
No. 9 425
No. 10 375
No. 11 425
No. 12 475
No. 13 525
No. 14 625
No. 15 725
No. 16 825
No. 17 1025
No. 18 1225
No. 19 1425

Each end of each cable is tagged with the number of the corresponding mine.

MATERIAL FOR AND DUTIES ON THE WATER.

Q. What apparatus is taken out on the distribution-box boat?

A. One distribution-box, 1 buoy for same, 1 mooring-rope for attaching buoy to distribution-box, 1 anchor sufficiently heavy to hold distribution-box boat, 1 anchor buoy (keg), and rope for same, 2 anchor shackles (1 for anchor and 1 for box), 1 pair field glasses, alcohol, 2 alcohol lamps, cable tags, Turk's head, collars, cotton waste, 2 files, 2 hammers, 2 heavy lines, knives, marline, 2 marline spikes, 1 megaphone, 2 monkey wrenches, 2 pliers, protective tape, rubber cement, rubber tape, 2 scissors, tin-foil, telephone, brass connectors, lashings.

The planter may locate the distribution-box boat anchor, and in that case it, together with its buoy, would not be taken out in the distribution-box boat.

Q. How and in what way are the cores of cable numbered?

A. They are numbered by the non-commissioned officer in charge of the boat, who establishes communication with the casemate, using the boat telephone, and working under the instructions of the casemate electrician.

Nos. 1, 13, and 19 are easily selected by means of their special marking; No. 19 is the center core; No. 13 is the marked core in the inner row of six; and No. 1 is the marked core in the outer row of twelve.

In the seven-cored cable there are no marked cores, the cores being numbered under the instructions of the casemate electrician.

Q. How is multiple cable laid?

A. It is transported to the planter by tramway, hoisted by steam-derrick to the _forward jacks_; it is then joined to the "shore ends" of the cable; the planter then steams to the distribution-box buoy and passes the end of the cable to the distribution launch, where a Turk's head is made and all is ready to receive the single-core cables for planting.

PLANTING OF MINES.

Q. How are single-core cables prepared?

A. 1^o If the single-core cable has not been cut and coiled in
loading-room, place reel on jacks, cut 20 feet off the end, unreel
to lengths given previously, cut and tag with mine number.

2^o Carry cable No. 19 on port side to after deck, keeping tagged
end forward and coil in figure eight, keeping tagged end on bottom.

3^o Make Turk's head on each end, first slipping tagged end through
a mine cap.

4^o Continue the operation above in the following order:

Nos. 1 to 9 starboard side.

Nos. 10 to 19 port side.

Q. Describe how to place mines aboard and to attach to cables preparatory to being planted.

A. 1^o Place mine buoys, anchors, mooring-ropes, raising-ropes,
shackles, sister hooks, etc., aboard forward and in convenient
places.

2^o Place loaded mines aboard last, nine on starboard and ten on
port.

3^o Cut to proper length the loading wire, make a tapped joint with
S. C. conductor with Turk's head, previously prepared through mine
cap.

4^o Fasten mine cap on mine, lash cables to bales, shackle
mooring-rope to mine, and anchor, lash mooring-rope to mine cable
every 5 feet (not done if automatic anchor is used).

5^o Cut raising-ropes 50 feet plus depth of water and attach one
end to anchor by anchor knot, the other end to mine cable by two
half hitches and a serving of marline, secure at a few other points.

6^o Attach about 60 feet small rope to mine buoys and mark this
rope every 5 feet, slip free end through maneuvering ring, and tie
to buoy. (The mines, anchors, cables, raising-ropes, and mine buoys
are now ready to be planted.)

Q. Explain how to sling the mine and anchor, and prepare it to "let go."

A. 1^o Mouse upper hooks of differential blocks and lash well with
marline the tripping hooks.

2^o Sling the anchor to the tripping hook on the differential block
of the forward davit, swing clear of rail, and lower close to water.

3^o Perform similar operation with mine from after davit.

Q. Describe the method of planting.

A. The planter now moves to the distribution-box boat, the latter to the port, No. 10 cable is passed to the same, planter now moves to No. 10 buoy, and when mine is abreast, the command "let go" is given.

The tripping hook of the mine is released first, and that of the anchor immediately after. The planter now circles to starboard, passes to the rear, and comes up to the distribution-box boat to the starboard. No. 9 is now passed, and planter moves forward to the position of this mine, plants it, and returns to distribution-box boat to repeat the operation till the group is planted.

CAUTIONS TO BE OBSERVED.

Men operating tripping hooks keep their feet free from all cable. Men on after deck must keep entirely free of all cable while being spent when planter is passing from distribution-box boat to mine buoy.

If dynamite is used as explosive all mines should be covered with paulines or burlap to protect them from the direct rays of the sun.

Q. Name the apparatus on the boat used in planting mines.

A. Derricks, catheads, snatch-blocks, steam-winches, insulated cable, cable-drum frames, circuit detector, boat-hooks, sounding-lines graduated to feet, davits, differential blocks, mooring-ropes, raising-ropes, buoyant mines and anchors, shackles and extra split pins for same, lashing-rope, alcohol, 2 alcohol lamps, 1 cable cutter, cable tags, Turk's head, collars, cotton waste, 4 files, 4 hammers, 6 heaving-lines, knives, marline, 2 marline spikes, 1 megaphone, 2 monkey wrenches, 4 pliers, protective tape, rope, rubber cement, rubber tape, 2 scissors, 1 set of stencil numbers, tin-foil, and a measuring line which has marks every 100 feet, with double marks at 300 and 600 feet.

Q. Give a method for marking the positions at which mines are to be planted.

A. The distribution-box is located first, a buoy and anchor being used as the mark. The center point of the group is located next, then the two ends of the group. The launch is directed over the spot selected from the map for the distribution-point by means of base-end instruments at the primary and secondary stations (these two instruments being set at the azimuth of the selected spot), and by signals from these stations the launch drops the anchor and buoy when it is at the intersection of the vertical cross-wires of each instrument. The launch marks the center of the group by moving approximately perpendicular to the line of mines to the desired distance. The line of mines is then determined by taking bearings and objects on shore (previously determined from the map) or by a similar method to that of locating the distribution-box buoy. Small planting-buoys are used for this purpose. The distribution-box buoy is usually a large keg or vinegar-barrel.

Q. How are soundings made?

A. By starting from either end of the "located group" and making a sounding at every 100 feet.

SMALL BOAT DRILL.

Q. Explain how a small boat used for marking and locating is managed, and give the commands necessary.

A. Upon leaving wharf, "Shove off!" performed by designated man.

To raise oars preliminary to rowing: "Up oars!" all oars being held vertically, opposite rowlocks, blades athwart boat.

To lower oars into the water: "Let fall!"; all oars are dropped easily into the water, without splashing, and quickly adjusted into the rowlocks, and then held in position of "Oars!" (See below.)

To move the boat forward: "Stand by to give way together!--GIVE WAY TOGETHER!" the boat being propelled forward at the latter command, all the men taking a slow uniform stroke, being guided by No. 1, feathering their oars as they come out of the water and move forward.

To cease rowing temporarily: "Oars!"; at this command the oars are raised out of the water to a horizontal position, blades parallel with the surface of the water.

To rest without taking oars from rowlocks: "In oars," when oars are drawn in and placed with handles under gunwales on opposite side of boat from rowlocks.

To move backward a short distance: "Back water!" executed opposite to "Give way together!"

To stop boat: "Hold water!"; the oars are held rigidly in the water, blades vertical.

To stop boat quickly, as if running on a rock: "About face! hold!" when the oarsmen turn about and hold blade in water, stopping momentum of boat.

To turn to port: "Pull starboard, back port!" (To turn to starboard, the opposite).

To make a landing: "In bow!"; the bow oar is raised vertically, then lowered into its place in the boat, and the bow man takes the boat-hook and guides boat gently into its place.

To cease rowing: "Way enough!"; the oars are raised vertically, shoved properly in place.

CORDAGE.

Q. Name the important knots used in mine-work.

A. Anchor-knot or fisherman's bend, square knot, clove-hitch, bowline, stopper, whipping, and short splice. (See plate of knots for gun-companies.)

THE U. S. MAGAZINE RIFLE.

See Examination for Second-class Gunners, for Gun-companies.

FIRST-CLASS GUNNERS.

CARE AND PRESERVATION OF MINE MATERIAL.

Q. How are mine-cases preserved and cared for?

A. They are painted light gray on the outside, and the screw-threads covered with a mixture of lard-oil and white lead (4 parts of tallow to 1 white lead). They are also either painted or covered with protective material on the inside. They are then stored on suitable racks inside a "torpedo storehouse."

Q. How are all bearing surfaces, such as screw-threads, prepared for storage?

A. By first thoroughly cleaning them with brushes, kerosene, waste, etc., and then covering with the above mixture of white lead and tallow.

Q. How is the motor-generator cared for?

A. Fill all oil-holes, and keep all parts free from dust and foreign material; see that all connections are tight; see that all brushes are in good condition, and replace worn ones by new ones. Use very fine _sandpaper_ for slight inequalities of the commutator.

Q. How are the mine-panel and the switchboard cared for?

A. See that all bolts to busses are tight, that all lamps are screwed home, that all contacts are clean and free from gum or dirt, that all switches work properly and all contacts correctly made.

Q. How should electric lights be cared for?

A. They should be kept clean and polished. Any snap-switch that sparks badly should be replaced. No verdigris should be allowed to accumulate on any brass fittings. When a lamp becomes dull or black inside, a new one should replace it. When any fuse is blown out, new ones should be put in. (Never use copper wire as a substitute for a fuse.)

Q. How should transformers be cared for?

A. Simply kept clean and in a dry place. They should be tested with a circuit-detector once in a while.

Q. How is the charging-generator cared for?

A. Keep free from dirt or rust, fill all oil-holes, clean the commutator with a dry rag, keep the brushes set so as to make good contact, and when not in use cover with a rubber paulin.

Q. How is the oil-engine cared for?

A. The oil-engine should be kept clean and nicely painted, all oil-holes filled, the water-tank filled and free from mud and sediment, the vaporizer examined from time to time and kept free from packed carbon, the piston clean and well oiled, the poppet-valves tight and free from any clogging material, the starting-torch clean and free from soot.

Q. When putting a piece of machinery out of commission what is done?

A. All bearing surfaces are exposed, cleaned, and covered with white lead and lard-oil or a similar substitute preservative. All small loose parts are removed, covered with cosmic wrapped in burlap, and stored under cover. The machine should also be housed.

Q. Name some of the principal cleaning materials.

A. Steel scrapers, button and wire brushes, waste, pomade, sandpaper, emery and crocus cloth, gasoline, kerosene, and alcohol.

Q. Name some preserving materials.

A. Cosmic, white lead, red lead, raw linseed oil, turpentine, beef tallow, drier, lamp black, pumice stone, varnish, asphaltum varnish, paint brushes, shellac, graphite paint and insulac.

Q. Name some uses of each.

A. Cosmic: Covering bright parts of engines, generators, motors, etc., when out of commission.

White Lead: (4 pts. W. L. to 1 of tallow) Used on screw-threads of mine cases, steel threads, compound plugs, bolts, nuts, washers, surfaces of flute joints, etc.

Caution: _Never use this on a joint where electrical contact is to be made_.

Red Lead: (100 pounds red lead ground in linseed-oil with 5 gallons raw linseed added.) On mine cases after being scraped. As a preliminary coat for iron surfaces of engines, generators, etc.

Raw Linseed, Turpentine, Drier, and Lampblack, for making different kinds of paint. Turpentine is also used to clean brushes, etc.

Tallow: For mixing with white lead to form a preservative.

Pumice-stone: When powdered and mixed with oil is used to rub down surfaces, as the first coat of varnish on an engine.

Varnish: As a finishing coat for metal and wood surfaces not exposed to heat or water.

Asphaltum Varnish: For painting anchors, distribution-boxes, mooring-sockets, shackles, sister hooks, junction boxes, iron work of operating boards and power panels, etc.

Shellac: For covering decks, spars, etc.

Graphite Paint: For painting hot parts of engines, etc.

Insulac: For preserving insulation on electrical instruments, etc.

Q. How is an engine painted?

A. All hot surfaces should be painted with black graphite paint. All other surfaces after being thoroughly scraped and sand-papered should be given a priming coat of red-lead paint. This should be lightly rubbed down with powdered pumice and oil, then two coats of preferably steel color metal paint applied and rubbed. Two coats of varnish are now applied and rubbed with pumice as above, after each coat becomes thoroughly dry.

HANDLING HIGH EXPLOSIVES.

Q. Name some high explosives used in submarine mining.

A. Wet gun-cotton principally, dynamite, and other high explosives that can be readily purchased in commercial life in case of emergency.

Q. Why is wet gun-cotton to be preferred as a high explosive?

A. Because it is perfectly safe to handle. It can only be detonated by first detonating a small piece of dry gun-cotton placed near it.

Q. What are some important precautions to be observed when loading mines?

A. 1^o Always wear rubbers when entering the magazine to get the
explosive. (The main supply is always kept in a cool magazine.)

2^o Never drop or slide along the floor boxes of high explosive.

3^o Do not expose high explosive to sun's rays or heat.

4^o Bring only one box to the loading-room at a time, then, when
used, burn the box and sawdust in a safe place.

5^o Place canvas or burlap on floor of loading-room, then place
mine on skids upon this.

6^o Use rubber gloves when handling dynamite.

7^o Sweep floor frequently and throw sweepings in water.

8^o After mine is loaded by use of funnel, carefully clean threads
with a soft brush, then smear plenty of ruberine on threads.

9^o Never saw or bore a dry guncotton cake.

10^o Never open a mine loaded with dynamite without first
consulting an officer.

11^o _Never thaw out dynamite near a stove._

Q. How is dynamite that is frozen thawed out?

A. Place the frozen dynamite in an open watertight can. Place this can in another can of warm water, such that the heat of the warm water only will do the thawing.

KNOWLEDGE AND USE OF THE PLOTTING-BOARD AND AZIMUTH INSTRUMENT.

Q. Describe the plotting board.

A. It is the same as that used for guns except the gun arm and its parts are not used. The scale is ordinarily 100 yards = 1 inch.

Q. How is it used for mine firing?

A. The ship is _tracked by plotting_ points of intersection of the primary and secondary arm every 20 seconds. After several positions are plotted a point is predicted at a certain interval of time ahead and by means of a "combination prediction and speed scale" the time of the arrival of the ship over the mine which was previously plotted on the board is obtained and this is the time of firing that mine. This is called "judgment firing."

Q. Describe and use the azimuth instrument.

A. See Examination for First-class Gunners for Gun-companies.

BATTERIES, GENERATORS, AND SEARCH-LIGHTS.

Q. Name the batteries used in mine work.

A. Casemate battery (storage--40 cells) and boat telephone battery (either storage or dry cells sufficient to give 15 volts).

Q. Describe the casemate battery. (See Fig. 103.)

A. This is a storage-battery of the standard chloride accumulator type. It is composed of 40 cells, type D-5 (D = size of plate 5, the number of plates). D-5 has two positive and three negative plates, each 6" × 6". Positive plates are of a brownish color, negative grayish. These plates are contained in a glass jar nearly filled with electrolyte (one part sulphuric acid to five parts distilled water by volume makes electrolyte of 1·210 specific gravity. _The acid must be poured into the water._)

These glass jars are placed in trays of sand and the trays rest on glass insulators. The normal charge and discharge rate of this battery is 5 amperes, although in starting the motor generator a much higher current is drawn from the battery. The voltage is about 80.

Q. What precautions are necessary to keep it in order?

A. 1^o Do not overcharge, overdischarge, or allow to stand
completely discharged. (Battery should be charged when discharge is
1.8 volts per cell.)

2^o Keep plates covered with electrolyte about ¾ inch above top of
plates. If not at proper height add distilled water.

3^o Keep cells free from sediment.

4^o A record of each cell (voltage and specific gravity) should
be kept each time the battery is charged, and this should be done
about once a week.

5^o The indications of a complete charge are: when positive
plates have a deep chocolate color, negative light slate, cells
gas freely, each cell reads about 2·5 volts, and 1.210 specific
gravity, and when no perceptible rise in voltage occurs for a lapse
of 10 to 15 minutes.

6^o If any low cells develop, bring them back into condition
immediately.

(_a_) If voltage is very low, look for sediment or foreign matter,
then charge separately.

(_b_) If specific gravity is very low take out some electrolyte and
add 1.200 specific gravity electrolyte. (This used to be 1.400.)

7^o Keep battery-room well ventilated, especially while charging.

8^o Never bring an exposed flame into battery-room while charging.
(The gases given off are explosive when mixed with air.)

9^o Keep the floor and all parts of the room clean, iron, copper,
and metal work free from corrosion; keep all connections tight and
clean; never allow verdigris to collect _anywhere_.

Q. Describe a searchlight.

A. It consists of an iron cylinder mounted on an iron pedestal in a yoke. The cylinder contains a parabolic mirror in the back, a series of glass strips in the front, and two "carbons" in the middle.

The electric current in passing through the carbons heats the points to a very high degree, producing a brilliant light. This light is reflected by the mirror towards the front, and the mirror, being of a curved form, also converges the rays of light. Underneath most searchlights are electric motors for traversing and elevating, and these motors are started or stopped by means of switches in a contrivance called a "controller," which is always placed at a distance from the light.

Q. Point out the following parts of a 36" searchlight: hand star-wheel for slow vertical movement; wheel for throwing out split nut used for connecting or disconnecting the drum from the base mechanism; wheel for slow horizontal movement; hand star-wheel for clamping turntable to center-pin for electrical control; wood handles on drum for moving drum by hand; hand-wheel for clamping hand star-wheel _A_ when electric control is used; controller-switch; controller-handle; controller fuse-box; controller-coupling for connecting cable from the projector; focusing-screw; socket for inserting wrench to operate lamp-switch used for cutting out feeding-magnet; socket for inserting wrench when feeding by hand; door used for adjusting the carbons and for cleaning the front door; door used when carbons are to be adjusted or changed; front door; door used when adjusting negative carbons or cleaning the mirror; horizontal peepsights; vertical peepsights; sliding case to be opened when lamp mechanism is to be inspected; projector main switch; latches for fastening base-sheeting; base-sheeting.

A. See Fig. 104.

Q. Describe the principal parts of the charging-generator?

A. The frame holds the field-magnets within which revolves an armature consisting of a winding of conductors and a commutator. Brushes made of carbon touch the commutator. The base rests on guides which permits of a motion of the generator to take up the slack of the belt.

Q. Point out the following parts of the generator: frame, base, field-coil, commutator, brushes, shaft, pulley, adjusting-screw, rocker-handle, magnet-frame bolt, brush-holder, brush stud-cable, rocker, bearing-cup, journal-box, pole-shoe, pole.

A. See Fig. 105.

Q. Point out the following parts of the oil-engine: cylinder-casing, vaporizer, vaporizer-cap, vaporizer-cover, vaporizer-cover lid, valve-box journal, valve-box sleeve, spray-nozzle, horizontal valve, horizontal-valve spring, vertical valve, vertical-valve spring, valve-box, valve-box screw-cap, valve-box coupling, overflow-glass, oil-pump can, oil-pump plug, oil-pump plunger, oil-pump plunger-spring, oil-pump plunger-head, oil-pump plunger-head guide, oil-pump gauge, oil-pump body, bed-plate, bearing-cup, splasher, oil-tank, oil-filter, filter-cock, worm-gear, gear-wheel, gear-guard, crank-shaft, crank-pin oiler, piston, connecting-rod, cam-shaft, governor-wheel, governor-pinion, governor-counterpoise, crank-shaft, governor-balls, governor-counterweight, air-valve cam, exhaust-valve cam, cam rollers, cam shifter, locking-handle, air-valve, exhaust-valve, cylinder-lubricator, cylinder-lubricator pulley, fly-wheel, fly-wheel key-guard, splasher.

FIG. 105.]

FIG. 106.]

A. See Fig. 106.

Q. Name some important points to be observed in caring for the generator.

A. 1^o Keep it perfectly dry.

2^o Keep it perfectly clean.

3^o Do not let pieces of iron or steel come near it when running.

4^o Keep the belt adjusted.

5^o Keep the bearings well oiled.

6^o Keep commutator clean and smooth (use fine sandpaper only, then
a soft cloth and some oil or vaseline, then dry thoroughly).

7^o Keep brushes in trim and making good contact.

8^o Do not allow armature to heat badly, or it will suddenly burn
out.

9^o Keep brushes on neutral point to prevent sparking. There is
usually a mark on the dynamo to show this, if not, rock brushes
until sparking ceases.

10^o Keep covered when not using.

11^o Keep connections clean and tight.

12^o Never overload it.

CASEMATE APPARATUS.

Q. Point out the following parts of the power panel:

Milli-ammeter and its protecting lamp.
Double pole circuit-breaker.
Single pole reverse current circuit breaker.
Direct current ammeter (two way).
Direct current voltmeter.
Alternating current voltmeter.
Double-pole double-throw lever switches.
Double-pole single-throw lever switches.
Receptacles.
Plugs.
Lamps.
D. C. busses.
A. C. "
Charging rheostat.
Field "
Resistance for reverse current circuit-breaker.
Terminal strips.
Fuses.
Fuse clips.

A. This must be learned at casemate.

Q. Point out the following parts of the operating panel:

Signal-block.
Master "
Mine "
Cable terminal block.
Single stroke gong and its switch.
Red lamp and white lamp, and use of each.
Resistance coil and its use.
Earth terminal.
A. C. "
D. C. "
A. C. jaw.
D. C. "
Testing switch on master block.
Firing switch.
Jumper.
Testing switch on mine block.
Automatic switch.
Mine switch.
Power switch.
Automatic switch release.
Solenoid.

The terminal block is provided with binding posts and clips.

A. This must be learned at the casemate.

Q. What is a motor generator?

A. A combination of a separate motor and a generator connected to the same shaft.

Q. What kind of a motor generator is the one in the casemate?

A. It consists of a motor driven by direct current and a generator which delivers alternating current. It has about 1-1/3 H. P.

Q. What is the voltage of each?

A. 80-110 for the motor and about the same for the generator.

Q. What is the object of the casemate transformer?

A. To raise the voltage from about 80 to 500 alternating current.

Q. Describe the mine transformer.

A. This will be learned in the casemate.

Q. Explain what switches you would set on power panel for automatic firing, the board having been previously tested and found by the electrician to be in order.

A. 1^o Put D. C. on busses
{ (_a_) Close double-pole circuit-breaker
{ (storage-battery), or
by { (_b_) Close S. P. reverse current
{ circuit-breaker and switch No. 2
{ to the right (post power), or
{ (_c_) Close S. P. reverse current circuit-breaker
{ and switch No. 2 to the left (casemate generator).

2^o Read voltage by plugging in proper receptacle.

3^o Close switch No. 3 up.

4^o " " " 4 " (or down).

5^o " " " 9 " ( " " ).

6^o Read A. C. voltage by plugging in proper receptacle.

8^o Close switch No. 8 up.

Q. Explain how to set operating panel for automatic firing.

A. All contacts, connections, switches, etc., having been previously tested and examined by the electrician and found in order:

1^o Close up the testing, automatic, mine, power, and gong switches.

2^o Close firing switch. */

_Note._--If one or more automatic switches cannot be made to stay
up, open the power switch for that mine before closing firing
switch.

Q. How would you fire by judgment?

A. Conditions being as above, lift the automatic switch release of
the mine to be fired at the command "Fire".

Q. How are mines tested?

A. 1^o Put D. C. on D. C. busses.

2^o Open power switches on all mine blocks.

3^o Unscrew all green lamps except on panel being tested.

4^o Close switch No. 3 down.

5^o Close power switch of each mine in succession and read
milli-ammeter. This should be about 30 to 40 milli-amperes.

Q. Point out and describe the parts of a boat-telephone.

A. See Fig. 107.

Q. Describe how to connect up and use the boat-telephone.

A. 1^o Connect one wire of the casemate 'phone to either side of
the battery, and the other to the ground (waterpipe is a good
ground).

2^o The same end of the battery is connected to wire Nos. 1, 13, or
19 of the multiple cable leading to the distribution-box boat.

3^o Connect one wire of the 'phone in the D. B. boat to this same
core (No. 19, for example).

4^o Connect the other wire to an earth plate which is overboard.
(An earth plate is usually made of iron or copper.)

5^o The other terminal of the telephone battery has a permanent
connection to earth. These connections then place the two
telephones in parallel with the battery.

To call, press the push-button.

To talk, press the talking-switch.

Q. Point out and describe the parts of a wall-telephone composite artillery type.

A. See Fig. 108.

Q. Give the tests for telephones.

A. 1st. _Bell is not rung by its own magneto._

Analysis: 1. Short circuit on line.
2. Mechanical trouble in the bell.
3. Short circuit in the phone.
4. Open circuit in the phone.
5. Magneto does not generate.

Operator's test: With the receiver on the hook turn the magneto
handle briskly.

If the bell does not ring and the magneto turns hard, (1. Short
circuit on line) or (3. Short circuit in phone) is indicated, and
the operator proceeds as follows, trying to ring after each step:

Inspect for contact of lightning-arrester carbons: a piece of
writing-paper should pass between them easily. See that the ends of
the line and ground wires do not touch any other part after passing
through the binding-posts.

Disconnect the line and ground wires. If the bell rings now,
(1. Short circuit on line) is clearly indicated, but if it does
not ring and still turns hard, (3. Short circuit in phone) is
indicated.

If the handle does not turn hard, the operator takes up (2.
Mechanical trouble in the bell) and sees that the striker is not
bound by the metallic cap over it or by the wood of the box, also
that the armature can be moved by hand and that the striker will
touch the gongs when the armature is so moved. The first trouble
can be remedied; the others should be reported.

(4. Open circuit in the phone). Open the magneto box, see that
contact is made between shaft and spring at _U_ and between the
springs at _V_ when the handle is turned. The last may fail because
the shaft is caught at some place, as where it enters the box or
the collar on the shaft may have slipped or the springs may be
bent. The spring at _U_ may be held against the end of the shaft
with a pencil, during a test, to insure good contact. A spark seen
at _U_ or _V_ indicates poor contact. If the operator cannot easily
correct these faults, he should report as nearly as practicable
what trouble he found.

Test for (5. Magneto does not generate) by moistening the tips of
the fingers and touch terminals of magneto. Turn the handles, and
if no shock is felt, a failure to generate is indicated.

2d. _Bell is not rung by distant magneto._

Analysis: 1. Home phone out of order.

2. Distant phone out of order.

3. Line out of order.

Operator's test:

(_a_) Test for (1. Home phone out of order) by detaching the line
and ground wires and turning the handle.

(_b_) Test for (2. Distant phone out of order) at the distant
phone in a manner entirely similar to (1. Home phone out of order).

(_c_) See expert's test for line troubles.

_Can hear but cannot be heard._

Analysis: 1. Local circuit at fault.

(_a_) Battery, (_b_) connections or wiring, (_c_) transmitter,
(_d_) primary coil.

2. Distant receiver out of order.

3. Home secondary coil short-circuited.

Operator's test: Disconnect line and ground wires and
connect binding-posts _R_ and _C_ with a piece of wire, thus
short-circuiting the phone. Place the receiver to the ear
and scratch gently with the finger-nail on the inside of the
transmitter mouthpiece.

If this is distinctly heard, the local circuit and receiver are all
right.

If no sound results, put the receiver to the ear, lower and raise
hook lever, also open and close the two-way switch. If a distinct
click is heard for each of these, the local circuit is all right
but the transmitter may not be in good order and a report should be
made.

If no sound results from above, make sure that the switch contact
is good and no pivots are loose, that all contacts are good,
that the connections at battery terminals are good with no green
substance on the wires or posts, that the water in the jars is up
to the prescribed point, about an inch from the neck of the cell,
that the zincs and carbons are not touching, that the zincs are
not eaten off, and that the zinc of one cell is connected to the
carbon of the other, and that there are no crystals on the zincs
and carbons.

The operator should correct any of these that he can, reporting the
others.

For (2. Distant receiver out of order) the operator at the distant
phone should try the tests above. If these give no sound in his
receiver, he should try another receiver, if one is available. He
may try a new cord or substitute two pieces of wire for it.

3d. _Can neither hear nor be heard._

Analysis: This indicates general trouble:

1. In the phones.

2. In the line.

Operators' test: Go over the phone carefully, looking for poor
contacts, as when an insulated wire is put in the binding-posts,
binding-posts not screwed down tight, ends of wires passing through
post touching other parts, contacts at cells and condition of cells
as noted before. Disconnect the line and ground wires and test out
phones as indicated. See that ground wire is in the middle post. If
there are fuses in the line, see that they are not burned out. If
no trouble is found to exist when the line is disconnected, report
line out of order.

Transcriber's Notes

Obvious errors of punctuation and diacritics repaired.

Both "defense" and "defence" are used and have not been changed.

Both "guncotton" and "gun-cottom" are used and have not been changed.

Hyphen added: hand[-]wheels (p. 8).

Hyphen removed: War[-]ships (p. 2).

P. viii: 8-inch Non-disappearnig -> 8-inch Non-disappearing.

P. 2: first or second-slass gunners -> first or second-class gunners.

P. 7: verticle angle -> vertical angle.

P. 31: Tetlautograph detail -> Telautograph detail.

P. 35: singals "Ready" or "Misfire," -> signals "Ready" or "Misfire,".

P. 77: Frankfort Arsenal -> Frankford Arsenal.

P. 89: right-handed sope -> right-handed rope.

P. 101: each pir of front and rear stakes -> each pair of front and rear stakes.

P. 110: Thong and Bush -> Thong and Brush.

P. 123: EXAGERATED DIAGRAMS -> EXAGGERATED DIAGRAMS.

P. 144: on dial -> on the dial.

P. 148, table, last column: 6 1 -> 6 1/5.

P. 156: TABLE A.--TABLE OF WARSHIP CHARACTERISTICS was split in two to fit within a reasonable width.

P. 160: (See Armor-attack Sheet, Fig. 86.) -> (See Armor-attack Sheet, Fig. 87.)

P. 168: 36 Imperieuse (34B Warspite) -> 36 Imperieuse (36B Warspite).

P. 184: 2 alochol lamps -> 2 alcohol lamps.

P. 187: free fram any clogging material -> free from any clogging material.

End of Project Gutenberg's The Gunner's Examiner, by Harold E. Cloke