Torpedo
The torpedo, named after an electric shock-giving fish, was originally applied to explosive charges moored at sea (now called mines). The same name was also applied to explosive charges attached to the ends of spars projecting from the bows of small boats or attached to lines and towed by boats. This type of torpedo was used in the American Civil War by the Confederate submersible H.L. Hunley to sink the U.S.S. Housatonic in 1864.
In 1865 the modern torpedo appeared. An Austrian captain named Luppis devised a clockwork-driven, boat-shaped craft guided by lines attached to its rudder. It was, in effect, a small electric boat with an explosive bow steered fromshore. This proved to be too difficult to operate effectively, so Luppis took his idea to Robert Whitehead (1823-1905), the English manager of a marine engine factory in Austria. Whitehead developed a much better torpedo. His design was a spindle-shaped underwater missile driven by a compressed-air engine at six knots for a few hundred yards and carrying an explosive charge of eighteen pounds (8.2 kg) of dynamite in its head. Whitehead's device could stay at a set depth by a valve actuated by water pressure and linked to the horizontal rudders. In 1868 he added a balance chamber with a pendulum connected to horizontal rudders that automatically corrected any fore-and-aft tilt. Back in England, Whitehead demonstrated his invention. The British navy was impressed with his 16-inch (41 cm) diameter torpedo. Driven by two contra-rotating propellers, the device had a range of 1,000 yards (914 m) at 7 knots or 300 yards (274 m) at 12 knots. A British ship used one of these torpedoes in action in an 1877 battle.
The torpedo was improved in many ways after this. An Austrian invented a gyro-controlled steering mechanism in 1878. The British increased the range and speed by using a mixture of steam and oil vapor with compressed air to give a hot run instead of the original cold run under compressed air only. Torpedoes stayed much the same until World War II, when the Germans developed an electrically-driven one that proved impossible to track back to the submarine. The steam-powered ones had left tell-tale bubbles in their path. The Germans also developed torpedoes that acoustically homed in on ship propellers.
Modern torpedoes are impressive weapons. The United States Navy has a twenty-one-inch (53.4 cm) diameter design that is driven at high speeds by machinery using hydrogen peroxide for its fuel. The U.S. Navy also has Subroc, a device fired as a torpedo deep below the surface. It emerges from the water, flies like a guided missile, moves on an interception course toward the target, submerges again, acts as a homing torpedo, and finally explodes near the enemy like a depth charge. Many torpedoes incorporate passive or active homing systems or wire guidance in cooperation with electronic sensors. Due to the tremendous progress in miniaturization, there have been many small torpedoes developed for launching from helicopters. Another torpedo in use in the late 1990s is an antisubmarine rocket (ASROC) that launches a rocket-propelled ballistic missile containing an acoustic-homing torpedo.
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