HSwMS Sjöormen (Sor)

History
Sweden
Name	Sjöormen
Builder	Kockums
Laid down	1966
Launched	25 January 1967
Commissioned	31 July 1968
Decommissioned	1997
Fate	Sold to Singapore in 1997
Singapore
Name	RSS Centurion
Acquired	28 May 1999
Commissioned	26 June 2004
Status	Active
General characteristics
Class and type	Template:Sclass-
Displacement	1,130 t (1,112 long tons) surfaced 1,210 t (1,191 long tons) submerged
Length	50.5 m (165 ft 8 in)
Beam	6.1 m (20 ft 0 in)
Draught	5.8 m (19 ft 0 in)
Propulsion	2 × Hedemora Diesel generators 1 × electric motor 1 shaft
Speed	20 knots (23 mph; 37 km/h)
Complement	25 officers and enlisted
Armament	4 × (533 mm (21 in) torpedo tubes) 2 × (400 mm (16 in) torpedo tubes)

HSwMS Sjöormen, Sw. meaning sea serpent, was the lead ship in the Swedish submarine class Sjöormen, project name A11. The planning of the ships included a number of different AIP-solutions including nuclear propulsion, however the ships where finally completed with for the time extremely large batteries. The ship was a single hull submarine, with hull shape influenced by the American experimental submarine USS Albacore (AGSS-569). The hulls was covered with rubber tiles to reduce the acoustic signature (Anechoic tiles), at this time a pioneer technology. The Sjöormen-class was also the first in the world to use a cross-rudder. The submarine served in the Swedish navy for almost 30 years and was then after upgrades sold to Singapore in 1997 together with its four sister ships.

References

{"Från Hajen till Södermanland", Granholm, 2003 (Swedish submarines during 100 years)