The holes in some instances are from 6 to 11 inches in length, and 2-1/2 inches in height. Angle of depression 20°, of elevation 30°, and of direction 360°.
Weight of the gun 3-3/4 cwt., and weight of carriage 2-1/2 cwt.
Hotchkiss Torpedo Gun.—This gun consists of a group of five barrels, revolving on a central shaft, a breech block, containing the firing mechanism, a feeding hopper, and the necessary hand crank for training and firing. The gun is mounted on trunnions attached to a vertical column, which rests in a suitable socket bolted to the ship's side; by this means a universal motion is obtained.
The essential difference between this and the Nordenfelt gun is, that the barrels and mechanism are put into rotatory motion.
Another point of difference is that single shots only can be fired, and not a volley, as in the Nordenfelt gun.
With the Hotchkiss gun, only some thirty shots can be fired in one minute at an advancing torpedo boat. The weight of the Hotchkiss steel shot is about 1 lb., but owing to the low velocity of the gun, its penetrative power is little more than that of the Nordenfelt 1/2 lb. bullet.
The object to be gained in firing at an attacking torpedo boat is to sink her, and not merely to kill or disable her crew, for supposing the attack to be made with a contact spar torpedo, and the boat to have reached within 300 yards' distance from the ship, then, even if all the crew (probably two or three men) were disabled or killed, the boat would, if not sunk, still carry out its work of destruction; therefore the projectiles to be used under such circumstances should be only those capable of penetrating a torpedo boat's plates, i. e., solid steel shot, not shells.
Diving.—In laying down and in picking up submarine mines, divers will be found extremely useful; also in clearing a passage in a river, &c., of an enemy's torpedoes in time of war. During the late Turco-Russian war, the harbour of Soukoum Kaleh taken by the Turks was popularly supposed to have been cleared of its mines by native divers (Lazees), but as the torpedoes so captured were never seen at Stamboul, it must have been a stretch of imagination; probably such would have been done, had there been any mines in the harbour to clear away.
The following is a general description of Messrs. Siebe and Gorman's improved diving apparatus.