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 tons surfaced 1,560 tons 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
Time to activate	1938–1969 (RN)
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.

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 class one of the most advanced submarine classes in service at the time.^[2]

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.