torpedoes

torpedoes were widely employed during the Second World War. MTBs and their equivalents, destroyers, cruisers, and even some battleships, were equipped with torpedo tubes for use in fleet actions; and they were also launched from aircraft, notably at Taranto by the British, at Pearl Harbor by the Japanese, and in the carrier v. carrier naval actions during the Pacific war (see carriers, 2). But a ‘fish’ (‘eel’ in the German Navy) was most deadly when fired, without warning, by a submarine (see Figure for typical torpedo).

A torpedo was, in fact, a miniature submarine in itself; but the depth-keeping and steering mechanisms were fully automatic. Until mid-1940 the depth-keeping of German torpedoes was erratic and there were numerous failures. American submariners, for some 20 months, also suffered from faulty weapons which did not explode and one German naval historian also comments on the lack of reliability of ‘the depth keeping and firing mechanisms’ of Soviet torpedoes used by the Black Sea Fleet ( F. Ruge, The Soviets as Naval Opponents, Cambridge, 1977, p. 101).

Typically, a semi-internal-combustion or turbine-propulsion torpedo was 533 mm. (21 in.) in diameter and 6.1 m. (20 ft.) long. An air bottle, to supply the engine, occupied about one-third of the length. It could take a heavy warhead of 270–393 kg. (595–866 lb.) 3–5 km. 2–3 mi.) at 45 knots or nearly 13 km. (8 mi.) at 30 knots, but the ideal range was about 1,100 m. (1,200 yd.). The longer ranges were academic unless a large number of fish were fired in a spread salvo like the opened fingers of a hand or successively in a ‘hosepipe’ which had the same effect by virtue of target travel. The chances of hitting an evasive target with only one or two torpedoes at more than a mile (l.6 km.) were low, though the Germans improved the odds at long range by using the Federapparat (spring apparatus) torpedo, or FAT, and Lagenunabhängiger (independent of target's inclination) torpedo, or LUT, which crossed and recrossed a convoy's path. Against ‘easy’ merchantmen, however, U-boats usually employed single-shot 30-knot, cheap and simple battery-powered electric ‘eels’ which, unlike ‘thermal’ oil-fuelled (or alcohol for USN turbine-drive) torpedoes, left no revealing wake on the surface. American submarines were similarly equipped from late 1943 and by 1945 were using them in 65% of attacks. The Royal Navy clung to oil-air thermal weapons scarcely changed from a 1928 design except that a magnetic-influence pistol—which was unreliable but could be more damaging because it exploded the 350 kg. (770 lb.) warhead beneath a target's pull—was sometimes used.

Torpedoes: Principal types

Origin	Propulsion	Speed/Range(n, miles) nautical miles=2,000 yards=1,829 metres	Explosive Weight	Use
Source: Contributor.
France
549 mm (21.6 in)	Thermal	35/3.8	308 kg (678 lb)	S/M
Germany
533 mm G7e	Electric	30/2.7	297 kg (653 lb)	S/M
533 mm G7a	Thermal	44/3.3	299 kg (658 lb)	General
Italy
533 mm Veloce	Thermal	49/2.2	113 kg (249 lb)	General
450 mm (17.7 in)	Thermal	44/1	110 kg (242 lb)	MAS (Torpedo) boats
Japan
610 mm (24 in) 93	Oxygen	49/12	499 kg (1,098 lb)	Surface ships
533 mm 94	Oxygen	45/2.5	393 kg (865 lb)	S/M
UK
533 mm (21 in) MkVIII	Thermal	45/2.5	350 kg (550 lb)	S/M
457 mm (18 in) MkXII	Thermal	40/0.75	176 kg (387 lb)	Aircraft
533 mm MkIX	Thermal	40/5	340 kg (748 lb)	Destroyers/Cruisers
USA
533 mm 14	Turbine	46/2.25	272 kg (598 lb)	S/M

The Japanese secretly developed exceptionally fast, reliable, long-range, and virtually trackless oxygen-fuelled torpedoes in the 1930s. The type 93 ‘Long Lance’ for surface ships was huge—610 mm. (24 in.) in diameter, 9 m. (30 ft.) long—delivering half a ton of explosive (508 kg.) out to 19 km. (12 mi.) at 49 knots. Fired in sufficient numbers to create a broad swathe of ‘torpedo water’, it was extremely effective against Allied warships in several naval engagements during the Pacific war (see Tassafaronga, for example). The smaller oxygen-fuelled submarine version had a shorter range (4 km./2.5 mi.) than the conventional German air-oil ‘eel’ (5.3 km./3.3 mi.), but a larger warhead (393 kg./866 lb. against 299 kg./659 lb.). Italy had some fast (48–50-knot) torpedoes but range was only 3.2 km. (2 mi.) and warheads were comparatively small at 250–270 kg. (551–95 lb.). For homing torpedoes see guided weapons; see also human torpedoes.

Richard Compton-Hall