HSwMS Sjöhunden (Shu)

For other ships with the same name, see HSwMS Sjöhunden.

HSwMS Sjöhunden (Shu), Sw. meaning sea dog, was the fourth ship of the Swedish submarine class Sjöormen, project name A11.

HSwMS Sjöhunden underway between 1968-1997
History
Sweden
Name	Sjöhunden
Namesake	Sjöhunden
Ordered	1966
Builder	Karlskrona
Launched	21 March 1968
Commissioned	25 July 1969
Decommissioned	1997
Homeport	Stockholm
Motto	Cave canem (Beware of the dog)
Nickname(s)	Shu
Fate	Sold to Singapore in 1997
Singapore
Name	Chieftain
Namesake	Chieftain
Acquired	28 May 1999
Commissioned	26 June 2004
Decommissioned	25 November 2024
Homeport	Changi
Status	Decommissioned
General characteristics
Class & 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)

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.^{[citation needed]} The ship was a single hull 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 pioneer 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.^[1][2]

Service history

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.

HSwMS Sjöhunden was renamed RSS Chieftain after Singapore acquired the boat on 28 May 1999. She was commissioned into the Republic of Singapore Navy on 26 June 2004 after a major refit. On 25 November 2024, she was decommissioned after 20 years of service.

Gallery

• HSwMS Sjöhunden & RSS Chieftain gallery
• 
  HSwMS Sjöhunden being launched on 21 March 1968.
• 
  RSS Chieftain during refurbishment in Sweden
• 
  RSS Chieftain in 2007.
• 
  RSS Chieftain in 2007.