The horizontal lever k, which carries the lever m and propeller e, rotates on the top of the fuze pillar f, and is prevented from rising by means of a screw. The torpedo being let go, the safety pin o is pulled out by means of a line which is attached to it. The propeller will not revolve whilst the torpedo is drifting with the current, but the instant it is stopped by the action of the current the wheel will be caused to revolve, and after a few revolutions it will unscrew the barrel from under the end of the lever k, and the latter, dropping the hammer n, will be forced by the spring p into contact with the thin steel plate h on the top of the fuze pillar, which blow is transmitted by means of the steel rod g to the percussion cap, and the torpedo exploded.
American Extempore Drifting Torpedo.—This form of drifting torpedo, which is readily made, was used in great numbers by the Confederates, and though not successful in sinking any Federal ships, caused their vessels considerable annoyance and delay.
At [Fig. 103] is shown a sketch of this torpedo. It consists of a tin case containing about 70 lbs. of powder. A stiff wire a, b passes through a hole punctured in a strip of tin c, and a stuffing box d; the end a of the wire is covered with fulminate, and so arranged that the friction caused by its passage through the strip of tin c will ignite it; a number of wires lead from b to pieces of driftwood on the surface e, e, e, and the case is supported at the proper depth by a line attached to a section of log.
Towing Torpedoes.—By towing torpedoes are meant those submarine machines which are so shaped and arranged, that when towed from a ship or boat in motion they will diverge to a considerable extent, thus enabling the towing vessel to pass clear of the ship attacked, and yet near enough to allow of the torpedo being brought in contact with some part or other of her hull.
Towing torpedoes were for the first time employed on actual service during the late Russo-Turkish war, when a modified form of the well-known Harvey torpedo, designed by a German officer, was used by the Russians, but in no case was it successful.
In this class of submarine offensive machines may be placed the following:—
- 1.—Harvey's towing torpedo.
- 2.—Menzing's towing torpedo.
- 3.—The French towing torpedo.
Harvey's Torpedo.—This form of towing torpedo was invented conjointly by Captain John Harvey and Commander Frederick Harvey, R.N., and is intended to be used at sea both as a means of offence and defence.
At [Fig. 104] is shown in elevation the small sized Harvey towing torpedo, in which all the latest improvements that have been devised are represented.