The situation of the great guns upon the lower gun-decks when they are run in clear of the port, and secured. The breech being let down, the muzzle rests against the side above the port; they are then secured by their tackles, muzzle-lashings, and breechings. Over the muzzle of every gun are two strong eye-bolts for the muzzle-lashings, which are 3-1/2-inch rope. When this operation is well performed, no accident is feared, as every act is one of mechanical skill. A gun is sometimes housed fore and aft to make room, as in the cabin, &c. Ships in ordinary, not in commission, are housed over by a substantial roofing.