HSwMS Sjöormen in August 1967
History
Sweden
Name	Sjöormen
Builder	Kockums
Laid down	1966
Launched	25 January 1967
Commissioned	31 July 1968
Decommissioned	1997
Motto	Esse non videre (To be without being seen)
Nickname(s)	Sor
Fate	Sold to Singapore in 1997
Singapore
Name	Centurion
Namesake	Centurion
Acquired	28 May 1999
Commissioned	26 June 2004
Decommissioned	11 March 2015
Homeport	Changi
Fate	Scrapped
General characteristics
Class and type	Sjöormen-class submarine Challenger-class submarine
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 (37 km/h; 23 mph)
Complement	25 officers and enlisted
Armament	4 × 533 mm (21 in) torpedo tubes 2 × 400 mm (16 in) torpedo tubes

HSwMS Sjöormen (Sor), Sw. meaning sea serpent, was the lead ship of the Swedish submarine class Sjöormen, project name A11.^[1]

Development

The planning of the class 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-hulled submarine, with hull shape influenced by the American experimental submarine USS Albacore. The hull was covered with rubber tiles to reduce the acoustic signature (anechoic tiles), at this time a pioneering technology. The Sjöormen class also pioneered the use of an x-shaped (as opposed to cross-shaped) rudder as a standard (as opposed to experimental) feature.

Service in Sweden

The submarine served in the Swedish Navy for almost 30 years and was then sold to Singapore in 1997 together with its four sister ships.

Service in Singapore

HSwMS Sjöormen was renamed RSS Centurion and Singapore reacquired the boat on 28 May 1999. She was commissioned on 26 June 2004 after a major refit. After 11 years in the Republic of Singapore Navy, she was decommissioned on 11 March 2015 and scrapped. Her fin and sail were preserved as a memorial at the Republic of Singapore Navy Museum.

Gallery

• HSwMS Sjöormen & RSS Centurion gallery
• 
  HSwMS Sjöormen underway in 1968.
• 
  HSwMS Sjöormen underway in 1968.
• 
  HSwMS Sjöormen underway in 1968.
• 
  HSwMS Sjöormen underway in 1968.
• 
  HSwMS Sjöormen underway in 1968.
• 
  RSS Centurion leading a combined US and RSN task group during Cooperation Afloat Readiness and Training (CARAT) 2004.

References