Torpedo

A modern torpedo is an underwater ranged weapon launched above or below the water surface, self-propelled towards a target, and with an explosive warhead designed to detonate either on contact with or in proximity to the target.

Historically, it was called an automotive, automobile, locomotive or fish torpedo; colloquially called a fish. The term torpedo was originally employed for a variety of devices, most of which would today be called mines. From about 1900, torpedo has been used strictly to designate a self-propelled underwater explosive device.

While the battleship had evolved primarily around engagements between armored warships with large-calibre guns, the torpedo allowed small torpedo boats and other lighter surface vessels, submarines/submersibles, even improvised fishing boats or frogmen, and later light aircraft, to destroy large ships without the need of large guns, though sometimes at the risk of being hit by longer-range artillery fire.

Modern torpedoes can be divided into lightweight and heavyweight classes; and into straight-running, autonomous homers, and wire-guided. They can be launched from a variety of platforms.