British T-class submarine

HMS Thorn
Class overview
Name	T class
Operators	Royal Navy  Royal Netherlands Navy  Israeli Navy
Preceded by	Grampus class
Succeeded by	U class
Completed	53
General characteristics
Type	Submarine
Displacement	1,290 long tons (1,310 t) surfaced 1,560 long tons (1,590 t) submerged
Length	276 ft 6 in (84.28 m)
Beam	25 ft 6 in (7.77 m)
Draught	12 ft 9 in (3.89 m) forward 14 ft 7 in (4.45 m) aft
Propulsion	Twin diesel engines, 1,250 hp (930 kW) each Twin electric motors, 1,450 hp (1,080 kW) each Two shafts
Speed	15.5 knots (28.7 km/h; 17.8 mph) surfaced 9 knots (17 km/h; 10 mph) submerged
Range	8,000 nmi (15,000 km; 9,200 mi) at 10 kn (19 km/h; 12 mph) surfaced with 131 tons of fuel[1]
Complement	48
Armament	6 × bow torpedo tubes 4 × external torpedo tubes 16 torpedoes 1 QF 4-inch (100 mm) deck gun

The Royal Navy's T class (or Triton class) of diesel-electric submarines was designed in the 1930s to replace the O, P, and R classes. Fifty-three members of the class were built just before and during the Second World War, where they played a major role in the Royal Navy's submarine operations. Four boats in service with the Royal Netherlands Navy were known as the Zwaardvisch class.^[2]

At the start of the Second World War the T class was together with the British S and U class, Dutch O 21 class and German Type VII one of the most advanced submarine classes in service at the time.^[3]

In the decade following the war, the oldest surviving boats were scrapped and the remainder converted to anti-submarine vessels to counter the growing Soviet submarine threat. The Royal Navy disposed of its last operational boat in 1969, although it retained one permanently moored as a static training submarine until 1974. The last surviving boat, serving in the Israel Sea Corps, was scrapped in 1977.