Sjöormen-class submarine

300px RSS Chieftain
Class overview
Builders:	Kockums
Operators:	Swedish Navy Republic of Singapore Navy
Preceded by:	Draken class
Succeeded by:	Näcken class
Planned:	5
Completed:	5
Active:	4
Retired:	1
General characteristics
Displacement:	Surfaced: 1,125 t (1,107 long tons; 1,240 short tons) Submerged: 1,400 t (1,400 long tons; 1,500 short tons)
Length:	50 m (164 ft 1 in)
Beam:	6.1 m (20 ft 0 in)
Draught:	5.1 m (16 ft 9 in)
Propulsion:	1 shaft 2× Pielstick diesel 1× ASEA electric motor
Speed:	Surfaced: 15 kn (28 km/h; 17 mph) Submerged: 20 kn (37 km/h; 23 mph)
Complement:	23
Sensors and processing systems:	FAS
Armament:	4× 533 mm (21 in) Torpedo tubes 2× 400 mm (16 in) Torpedo tubes Mines

The Sjöormen class were a group of submarines built for the Swedish Navy in the late 1960s. They had a teardrop shape and were capable of diving to 150m. At the time of their deployment they were regarded as one of the most advanced non-nuclear submarine-classes in the world, incorporating many new features including x-rudder and anechoic tiles. Both speed and underwater endurance was at this time very high for a conventional submarine. The submarines were retired by Sweden in the early 1990s. In the late 1990s, four submarines were acquired by the Republic of Singapore Navy and relaunched as the Challenger class following modernisation and tropicalisation.

Ships

Ship Name	Builder	Launched	Commissioned	Status
HMS Sjöormen	Kockums	25 Jan 1967	31 July 1968	sold to Singapore as RSS Centurion
HMS Sjölejonet	Kockums	29 June 1967	16 Dec 1968	sold to Singapore as RSS Conqueror
HMS Sjöbjörnen	Karskrona Navy yard	9 Jan 1968	28 Feb 1969	sold to Singapore as RSS Challenger
HMS Sjöhunden	Kockums	21 March 1968	25 June 1969	sold to Singapore as RSS Chieftain
HMS Sjöhästen	Karskrona Navy yard	6 Aug 1968	15 Sept 1969	sold to Singapore as spare parts

References

Notes

Bibliography

• Conway's All the World's Fighting Ships 1947-1995

External links

• Official Kockums website on the Challenger class submarines