Torpedoes

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

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 an underwater self-propelled weapon. The original torpedo is a kind of fish: an electric ray.

While the battleship had evolved primarily around engagements between armoured ships with large-caliber guns, the torpedo allowed torpedo boats and other lighter surface ships, submersibles, even ordinary fishing boats or frogmen, and later, aircraft, to destroy large armoured ships without the need of large guns, though sometimes at the risk of being hit by longer-range shellfire.

Today's 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.

The word torpedo comes from the name of a genus of electric rays in the order Torpediniformes, which in turn comes from the Latin "torpere" (to be stiff or numb). In naval usage, the American Robert Fulton introduced the name to refer to a towed gunpowder charge used by his French submarine Nautilus (first tested in 1800) to demonstrate that it could sink warships.

The concept of a torpedo existed many centuries before it was later successfully developed. In 1275, Hasan al-Rammah described "...an egg which moves itself and burns."

...
Wikipedia