Submarine Torpedo (weapon)
Torpedo (weapon), self-propelled underwater naval weapon with an explosive charge, equipped with an internal-guidance system that controls its direction, speed, and depth. A typical torpedo is cigar-shaped, is 6 m (21 ft) long, has a diameter of 53 cm (21 in), and weighs about 1361 kg (about 3000 lb). Torpedoes are the principal weapons of the submarine; during World War II (1939-1945), torpedoes were also the principal weapons of the PT boat. In addition, torpedoes are used by antisubmarine surface vessels and airplanes.
Modern torpedoes are classified as steam torpedoes or electric torpedoes. Steam torpedoes have speeds from 25 to 45 knots and ranges from 4367 to 27,350 m (4000 to 25,000 yd). Their four major components are the warhead, air-flask section, afterbody section, and tail section. The warhead is filled with 181 to 363 kg (400 to 800 lb) of explosives. The air-flask section constitutes about one-third of the torpedo and contains compressed air and fuel and water tanks for the propulsion system. The afterbody section contains the propulsion turbines and the steering and depth-control devices. The tail section contains the rudders, exhaust valves, and propellers. Controls of the electric torpedo are similar to those of steam torpedoes, except that the large air flask is replaced by storage batteries and the turbines are replaced by an electric motor. Because electric torpedoes are more difficult to detect than steam torpedoes, more and more torpedoes today are electrically powered.
The modern torpedo is a self-propelled explosive projectile weapon, launched above or below the water surface, propelled underwater toward a target, and designed to detonate on contact or in proximity to a target. The original use of "torpedo" was for a variety of devices that would today be mostly called a "mine". However, from the First World War onwards "torpedo" was only used for an underwater self-propelled missile, often called colloquially a "fish".
While the battleship had evolved primarily around engagements between armoured ships with large guns, the torpedo allowed torpedo boats, other lighter surface ships, submersibles, and aircraft to destroy large armored ships without large-caliber guns, though sometimes at the risk of being hit by longer-range shellfire. In the Battle of Samar, destroyer-mounted torpedoes were the only weapons available to the U.S. task force capable of damaging opposing Japanese cruisers and battleships.
Today's torpedoes can be divided into lightweight and heavyweight classes; and into straight running, autonomous homers and wire-guided ones. They can be launched from a variety of platforms. Originally, the torpedo was primarily used in an anti-shipping role. This has been largely superseded by the missile, so the torpedo's main contemporary use is against submarines.