Torpedo

Torpedo can be ambiguous. Students of literature or history may come across the word in a very different sense from the standard current meaning, of

• 'an underwater weapon'. The first weapon to be given this metaphorical name was originally close to the modern 'depth charge':

it was a waterproof case containing an explosive charge which could be detonated by a timer. This had a 'stunning' effect on nearby vessels, or on people (and fish) swimming in the vicinity. Hence the name (see below for the older meaning). The first mobile contact weapon, which floated, was designed to be towed by a submarine which would pass under the target ship and bring the 'torpedo' into contact on the side from which the original approach had been made. This was later known as a 'towing torpedo'. (The technology developed into the 'moored torpedo', nowadays known as the moored 'mine'.) Surface vessels could carry such a device on a spar, the 'boom-torpedo', 'out-rigger-torpedo' or 'spar-torpedo'. Some - 'otters' - were towed at an angle from the parent vessel, taking up a divergent course. The divergence was caused by a vane or fin, similar to that used in the mine-sweeping device, a paravane.)

• • The name 'torpedo' became more appropriate when the newer weapon was developed, a self-propelled missile that travelled virtually unseen under the surface of the water, and detonated on contact with the target. These are now often 'homing torpedoes', mostly used from submarines, that now steer themselves onto their targets. Many words and phrases have developed from the older times when they were predominantly launched from surface vessels:
    • Torpedo boats (or M.T.Bs, Motor Torpedo Boats) were fast light vessels designed to be used in swarms to fire torpedoes at much heavier vessels, seen as vulnerable from their lack of manoeuvrability. To defend against them, a class of escort vessels was developed called torpedo boat destroyers, larger, even faster, and more heavily armed. These became valuable in escorting convoys and almost any vessels, against many threats, and are now usually known as destroyers.
      • Torpedo boats used by the German navy from 1932 and to the 1945 were known to the Allies as E-boat ('enemy boat'), though the Germans knew them as S-boot, for Schnellboot ('fast boat').
    • An aerial torpedo is an underwater missile dropped from an aircraft, such as a torpedo bomber. This type of aircraft, extensively used in the Second World War, is no longer used.
    • A torpedo lieutenant was a naval officer in larger ships in charge of the torpedoes and the torpedo tubes from which they were launched. In the Royal Navy, his title was conventionally abbreviated to Torps
    • In forms of football played with pointed balls, a torpedo kick is one where the motive force is applied to the point and along the long axis, so that the ball flies through the air 'like a torpedo' - without tumbling end-over-end.
    • The verb 'to torpedo' (torpedoed, torpedoes, torpedoing) has a literal meaning, 'to sink, or damage, by means of an underwater missile strike' - or, in older English, by any of the mines etc that were previously called 'torpedoes'; or even 'to stun' or 'to paralyse', by the action of the fish. Figuratively, it means 'to cause great damage to' something, often an argument, by an unforeseen deployment of a hitherto secret point: a speaker might, for example, torpedo a proposal seen as likely to succeed by pointing out that it is actually against the law to do as proposed. Ben Goldacre wrote in The Guardian: "torpedoing cherished ideas is a very good way to make a name for yourself in academia" (26/02/11[¹])
• Torpedo was originally the Latin name for a fish - the electric ray. There are several species of rays that go under this name: they can be found in temperate seas all over the world. They are all rays (cartilaginous fish, related to sharks). They live in shallow water, living in and feeding on the species in coastal sediments, and are liable to be stood upon by land dwellers, or disturbed by sea dwellers. Consequently, they have evolved the power of producing electric shocks, as a defensive weapon. They are related to the so-called electric eel (Electrophorus electricus), a freshwater fish (not a true eel, but from South America which can also produce an electric shock - but has evolved it as a hunting weapon as well as for defensive purposes. It too has been called 'the torpedo' since its discovery by Europeans, who related it to their experience of the ray found in the Mediterranean.

This electric ray (torpedo torpedo) has been known since ancient times. The Romans named it 'the torpedo' from the verb torpere, 'to be stiff or numb', because the shock from the ray is enough to stun or numb a human victim. It (and other electric rays, discovered more recently and called after it) is also known as the 'numbfish' or 'crampfish' in English. (Torpere is also the root of the adjective torpid.)

Etymological note & curiosity: as Julia Cresswell points out, it is a strange anomaly in the history of the word torpedo. It now refers to a weapon capable of speeds up to 80 knots, and ranges over 20 miles, but it began as a name for a sluggish fish (Cresswell relates torpere to the electric ray's bottom-dwelling habits, rather than its effect on its prey). And the weapon is far from torpid (= sluggish) in its character.