British Porpoise-class submarine

HMS Rorqual
Class overview
Name	Porpoise
Builders	Vickers Shipbuilding and Engineering Cammell Laird Scotts Shipbuilding and Engineering Company
Operators	Royal Navy
Preceded by	Explorer class
Succeeded by	Oberon class
Built	1956–1959
In service	1961-1980s
In commission	1956–1988
Completed	8
General characteristics
Type	Patrol/Attack submarine
Displacement	2,080 tons surfaced 2,450 tons submerged
Length	290 ft (88 m)
Beam	26 ft 7 in (8.10 m)
Draught	18 ft (5.5 m)
Propulsion	2 × Admiralty Standard range diesel generators, 1,650 hp (1,230 kW) 2 × English Electric main motors, 6,000 hp (4,500 kW) 2 shafts
Speed	12 kn (22 km/h; 14 mph) surfaced 17 kn (31 km/h; 20 mph) submerged
Range	9,000 nmi (17,000 km; 10,000 mi) at 12 kn (22 km/h; 14 mph)
Complement	71
Armament	8 × 21 inch (533 mm) torpedo tubes, 6 bow, 2 stern 30 × Mark 8 or Mark 23 torpedoes, later the Mark 24 Tigerfish

The Porpoise class was an eight-boat class of diesel-electric submarines operated by the Royal Navy. This class was originally designated patrol submarines, then attack. They were the first conventional British submarines to be built after the end of World War II. Their design was, in many ways, influenced by the German World War II-era Type XXI U-boats.