Torpedo is a self-propelled, underwater weapon used to damage ships and submarines. Modern torpedoes can be launched from submarines, surface vessels, or aircraft. Some are designed for attacking large groups of cargo vessels and fast warships. Other torpedoes are specifically used to combat deep-running submarines.
How a torpedo works.
Torpedoes are generally tube-shaped. They vary in size, weight, and mechanical apparatus, depending on their intended purpose. A typical torpedo has four sections. The nose section contains acoustic and electronic devices the torpedo uses to hunt and pursue a target. Behind the nose is the warhead section, which includes an explosive charge and the fuzing mechanism, which causes detonation. The center section houses systems that stabilize the weapon and control its direction. It also contains the torpedo’s energy source, which may be compressed air, batteries, or a fuel. The rear section, or afterbody, encloses the engine and propellers.
A torpedo is typically launched from a hollow tube pointed toward a target or the target’s future position. Or an aircraft may drop the torpedo, which is slowed by a parachute before it hits the water. A starting lever puts the engine into action when the torpedo enters the water. Power flows from the engine to the propellers, which drive the torpedo forward, and to the tail surfaces that steer the torpedo. Dual propellers counterrotate (turn in opposite directions), eliminating torque (twisting force) to prevent the torpedo from spinning in the water. As the torpedo hunts for the target, the fuzing mechanism automatically arms the warhead. When acoustic “ears” called hydrophones detect noise from the target, the torpedo is within acquisition range. It then leaves its hunting course and tracks straight toward the target. The warhead may be set to explode when the torpedo contacts a hull or when magnetic, acoustic, or pressure sensors indicate that it is within range of the target.
A special-purpose torpedo that provides greater accuracy and selectivity can be guided by wire to its target. This torpedo unwinds a reel of wire as it travels to the target area. The attacking ship or submarine sends steering signals over the wire. Another special type of torpedo called a wake homer senses the small air bubbles of a ship’s wake and follows them until the fuzing mechanism detects the ship.
An antisubmarine rocket (ASROC) system uses a warship’s sonar equipment to detect a submarine at long ranges. It then computes the target’s course and speed. The warship launches a ballistic (rocket-propelled) missile containing either an acoustic-homing (sound-detecting) torpedo or a depth charge. The rocket and other parts of the missile fall away in the air, and the torpedo, slowed by parachute, falls into the water. The acoustic-homing device then guides the torpedo to its target. A depth charge explodes at a predetermined depth.
History.
Until the 1900’s, the word torpedo was applied to a mine or any other explosive device used against ships. At first, none of these devices had means of propulsion. Surface vessels or submarines rammed a torpedo against an enemy ship or secretly attached the device to its hull. In the early 1800’s, the American inventor Robert Fulton experimented with long, narrow, minelike devices he called “torpedoes,” but there was little interest in his invention. During the American Civil War (1861-1865), the Union and Confederate navies each sunk an enemy ship with spar torpedoes. The torpedoes consisted of charges mounted at the end of a pole sticking out from the attacker’s bow. The charges exploded on contact with another vessel.
In 1864, Giovanni Luppis, a captain in the Austrian Navy, took a plan for a torpedo to the famous Scottish engineer Robert Whitehead. By 1868, Whitehead had developed the first real torpedo. Powered by compressed air, the torpedo was completely self-propelled.
Torpedoes used during World War II (1939-1945) were of simple mechanical or electrical design. They were aimed at surface vessels only, and they ran a straight course. They left a telltale wake of air bubbles behind them and made noise as they traveled. A maneuverable ship with an alert crew could evade them.
On the outside, present-day torpedoes resemble earlier ones. On the inside, however, modern torpedoes are vastly more complex. Modern warfare demands versatile, reliable weapons. Today’s torpedoes leave no wake behind them and are difficult to detect. They can track ships making evasive maneuvers. Today’s torpedo designs involve so many fields of science and are so complicated that the modern torpedo cannot be credited to any one person.
