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.