Shipborne Weapons - Torpedoes

2. Torpedoes
The modern definition for torpedoes came about during the 1870s as a self-propelled warhead that ran on or below the surface of the water. Previously the word torpedo also encompassed booby traps, land and naval mines and other 'hidden contact explosives'.
The first modern design for a torpedo came about in 1864 in Austria, where a naval officer proposed a manual rope-driven projectile floating on the water surface as a type of coastal defence. He brought the idea to Robert Whitehead, who thought of using first clockwork motors, then compressed air to power torpedoes. This culminated in the first true self-propelled torpedo, the Minenschiff (mine ship).
Gradual refinements improved performance but the basic compressed-air design remained essentially the same until 1904, when Whitehead's company developed the heated torpedo, which used injection and ignition of a liquid fuel into the compressed air to increase performance. The introduction of seawater as a coolant further increased performance by allowing more fuel to be burnt and later the steam generated from the seawater cooling the engine was also used as propulsion. As a result, by WW1 torpedoes could run 4 km at a high speed of 45 knots.
Between the war years, the Japanese tried substituting pure oxygen instead of plain compressed air (which contains only 21% oxygen) into their torpedoes. The result: the Type 93 'Long Lance' torpedo, reputedly the most advanced torpedo in the world at the time and even during WW2. It had a maximum range of 40km at 38 knots with a half-tonne warhead. By contrast, the standard U.S. destroyer-launched torpedo of WW2, the Mark XV, had a maximum range of 13.5km at 26.5 knots with a 375 kg warhead.
After WW2, types of propulsion for torpedoes diversified, including electric batteries, gas turbines and even rockets.
Most of today's torpedoes use either batteries or monopropellants, that is stable fuels that only react and produce energy under certain conditions. Most German and French torpedoes (including the Black Shark torpedo used on Malaysia's Scorpenes), are of the electric type. Most US and British torpedoes, however, use the Otto monopropellant gas turbine system. Examples include the Mark 48, 50 and 54 and the Tigerfish and Spearfish. Russian torpedoes use a mix of electric and fuel combustion systems.
A notable type of torpedo is the supercavitating torpedo, a torpedo that essentially forms a frictionless air bubble around itself. The Russian Shkval (Squall) is the apparent only example to date. Rocket-powered, this torpedo can run 13 km at an amazing 200+ knots!
Torpedoes have become an essential tool of naval warfare. Patrol boats, destroyers, cruisers, submarines and others carry them. Their hard-hitting capability ensures that they will be a force to be reckoned with for a long time to come.