Chapter II: Magazines and Shell-Rooms

CONSTRUCTION, LIGHTING, STOWING, AND FLOODING.

188. No details of internal arrangement should be more carefully considered and executed than those relating to the stowage and delivery of powder, since a defect in these particulars, apparently insignificant, may lead to the instantaneous destruction of the ship; or, with the incendiary and explosive projectiles now used, to her becoming, comparatively, an easy prey to an antagonist. Every possible precaution, therefore, is to be taken to accommodate the full allowance of powder completely; to guard it to the utmost against injury and accidental explosion; and to deliver it at the magazine, as required, with facility and certainty. To these ends, and in view of the fact that all the powder for great guns is now put up in cubical copper tanks, made water-tight, THE FORM OF MAGAZINES should be as nearly rectangular as the shape of the vessel will admit, and they should be built strong enough to resist sufficiently the effect of her working in heavy weather, and also the pressure of water they will have to sustain in case of being flooded.

189. All magazines should have a light-box for each alley at one end, and a passage to deliver powder at the other; and the magazine and its passage, considered as one, must be made perfectly water-tight by caulking the bottom and sides, and then lining them internally, first with white pine boards, tongued and grooved, and again with sheets of lead of extra thickness, soldered together, over these boards. Both these linings are to extend entirely over the bottom or floor, and all the way up to the crown on all the sides.

190. When the magazine reaches the ceiling of the ship it must be battened off two inches; the lining of the floor must be battened up one, and also the magazine-deck, so that water leaking through the sides of the vessel may run by and under, and not into the magazine.

An external lining of sheet-iron must also be resorted to as a protection against fire, and to prevent the intrusion of rats.

191. A magazine aft in a ship is to have its passage for delivering powder adjoining its forward part; and one forward in a ship is to have this passage adjoining its after part, in order that it may not be necessary to pass the powder over the light-box scuttle.

192. As many doors are to be cut in the bulkhead separating this passage from the magazine-room as there are alleys to be left in the latter, between the racks or shelves on which the tanks are stowed, and these doors must correspond with those alleys. They are not only to afford a means of entrance to the magazine, but also for passing the tanks in and out. Through the upper part of each door a small scuttle is to be cut,--two, if necessary,--for the purpose of passing the cartridges out of the magazine-room with the door itself closed; and it is to have a lid so arranged as to open outwards only, and to close of itself when the scuttle is not actually in use.

193. Sailing ships-of-the-line and frigates should have two alleys for each magazine. In screw-vessels of large class, where the shaft will interfere with this arrangement, two alleys for the forward magazine. In smaller vessels one alley will suffice. In all cases the alley is to be not less than two feet and ten inches in breadth, and it ought to be more, if practicable, to prevent confusion and delay. Each alley is to be illuminated by a separate light.

If there is room in the magazine, there should be space left, at the end nearest the light, for a man to pass from one alley to the other without going into the passage.

194. Ships with two magazines--one forward and the other aft--are to have them as nearly equal, in point of capacity, as the shape of the vessel and other circumstances will admit.

Magazines should be constructed as low down as possible. Their floors may rest on the keelson, but should not come below it. Their height should be equal, only, to an exact number of times the height of a powder-tank when lying on its side, in addition to the thickness of the shelving. An additional inch for each shelf should be allowed for play or spring. The whole height in the clear should be limited by the condition that a man standing on the floor may reach the upper tier of tanks with ease. Four tiers of 200-lb. tanks, three of them resting on shelves two inches thick, and the other on inch battens on the magazine-floor, will, with an allowance of one and a half inch for play and spring, require a height, in the clear, of six feet two inches. Both safety and convenience would suggest this as the maximum limit in height, even for the largest magazine. Three tiers of these tanks will require a height, in the clear, of about four feet eight inches.

If, however, in ships of great draught of water, it should be found practicable to extend the height of a magazine so as to accommodate five tiers of tanks, then the lower or ground tier may be laid so as to occupy the whole of the magazine-floor; and on the top of this tier, in the alley-way, a light false bottom is to be placed for the men to stand upon to enable them to reach the upper tier, which is the one that should first be exhausted. This false bottom should be made of gratings, and in sections convenient for speedy removal.

195. When it is impossible to avoid extending the sides of the magazine so far out towards the skin of the ship as to leave only an air-passage on either side, the crown should be at least six feet below the deep load-line.

In all cases where this crown is less than six feet below that line, the sides should be made susceptible of protection by allowing a space to interpose materials, such as sand, coal, or water in tanks, between them and the inner planking of the ship.

An average space of six feet or more on both sides will be sufficient. Under no circumstances, however well the sides be guarded, should the crown of the magazine, if it can be avoided, be less than four feet below the deep load-line.

196. It is proper to add, in connection with this most important subject, that in order to increase security against the effects of lightning, a magazine should be placed, if practicable, so as not to include a part of a mast.

197. All the metallic fixtures about a magazine, delivering-passages, and light-rooms, must be of copper.

198. Each delivering-passage is to have, for the distribution of powder, at least as many passing-scuttles communicating with the orlop or berth deck as there are chains of scuttles above. The powder-man will thus always find at the scuttle the proper passing-box.

MAGAZINE-COCKS.

199. Each magazine, as a whole--that is, including the delivering-passage--being made, as stated above, water-tight, is to be provided with an independent cock for filling it rapidly with water; a waste-pipe leading from above the upper tier of tanks to carry off the superfluous water; and a cock just at the floor for letting the water off when the magazine is to be emptied after having been flooded. Both the cocks must be turned from the deck above, each having a lever to its spindle for the purpose, distinctly marked, with engraved letters, what it is and how it is to be used, and kept secured by a proper lock, the key of which is to be kept among those of the magazines. A short pipe to lead the water down into the hold is to be attached to the emptying cock, and with this the waste-pipe is to connect. All are to be well boxed over for protection against injury. A perforated disk, or strainer, is to be secured inside of the hole, at the upper part of the magazine, for the waste-pipe. All couplings of hose shall conform to the general naval standard.

LIGHTING THE MAGAZINE.

200. The magazine is to be lighted by means of one regulation-lamp, to correspond with each alley of the magazine-room, placed in a box arranged for the purpose. This box, of which a portion of the magazine bulkhead forms a part, is to be lined, internally, with soldered sheets of copper, and have a few inches of water in it whenever the lamp is lighted. The entrance to it is at the top, through a scuttle in the deck large enough to admit the lamp. For single-decked vessels this scuttle may be surrounded by a composition coaming pierced with holes one-fourth of an inch in diameter, on the forward and after sides near the top. The cover must be so arranged that, when placed in one position, all the holes will be closed--by turning it half round, they are all open; thus supplying air to the lamp and carrying off smoke. In the portion of the magazine bulkhead just alluded to, and so as to throw as much light as possible into the magazine-room, an opening with great bevelling is to be cut, which is to be covered by two plane glasses of suitable thickness, somewhat separated from each other, one of which, that next to the lamp, must be permanently fixed; and the other, or that next to the magazine, is to be let into a wooden frame so that it may be easily removed, and thus both glasses cleaned at any time with convenience and safety. The glasses are to be held in place by brass screws, after being closely fitted and having their edges made perfectly tight. A small dome or reversed funnel of copper, where it can be conveniently done, is to be placed above the lamp and fitted with a pipe of the same metal to convey the smoke off. This pipe may pass up through the covering of the light-box, which is to have a plug-hole, lined with brass, for the purpose, and then led farther, if necessary, taking care, however, to consult perfect safety throughout.

The admission of air to the light-box may be from the division of the hold in which it is placed, by small holes, near its top, through its side or back, protected with copper wire-gauze, inside and outside of the box.

The ceiling and bulkheads of all magazines and shell-rooms should be thoroughly whitewashed.

STOWING THE MAGAZINES.

201. In the stowage of magazines, reference must be had to the Gunner's duties (Art. 36, Part I.), and to Arrangements for Delivering and Distributing Powder (Art. 180, Part I.). Ledges on the shelves, or a bar of wood to ship and unship with facility, will be provided for each tier of tanks, on both sides of the alleys, to secure them from getting out of place when the ship rolls.

The Inspector of Ordnance will furnish the commander of the ship with an exact plan of the magazine and shell-rooms, which shall be returned to the Inspector of the Yard at which the ship refits or is placed in ordinary, with any suggestions the Commander may have to make relative to practicable changes which will render the service more safe or convenient.

SHELL-ROOMS.

202. Rooms for the stowage of loaded shells require the same care in construction and protection against an enemy's shot, and in provision for lighting and flooding, as magazines. Therefore, they should always be built with reference to these objects, as well as to affording room enough to accommodate conveniently the number of loaded shells allowed in their boxes, stowed in bulk. Each should have one light, arranged like those for magazines.

203. In vessels partially armed with shell-guns, the best place, perhaps, for these rooms is immediately forward of the spirit-room, but not communicating with it; and in those armed entirely with such guns, the additional shell-rooms necessary may be, perhaps, more conveniently placed abaft, and adjoining the delivering-passage of the forward magazine, than elsewhere.

204. With the introduction of rifled cannon, and various special projectiles, it is essential to devote more care to the stowage of shells, in order to avoid confusion in battle. Not only each kind and calibre, but each length of fuze, is to be stowed in separate tiers.

DAMPNESS OF MAGAZINES AND SHELL-ROOMS.

205. Sponge clipped in a solution of salt water, dried and weighed, is a means of ascertaining if dampness exists in these places. If it become heavier, the room is damp.

VENTILATION.

206. Provision must be made, by means of grating-hatches, for sufficient ventilation in action, to supply the magazine-men with fresh air, and allow the dampness caused by perspiration to pass off; and fan-blowers are to be fitted to increase the supply of fresh air, and assist the ventilation. The magazine should be opened and aired, at least once a fortnight, for a few hours, on bright, clear days.