HSwMS Sjöhästen (Shä)

HSwMS Sjöhästen (Shä), Sw. meaning sea horse, was the fifth and last ship of the Swedish submarine class Sjöormen, project name A11.

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 (AGSS-569). The hull was covered with rubber tiles to reduce the acoustic signature (anechoic tiles), at this time a pioneer technology. The Sjöormen-class submarine 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
Sjöhästen was launched on 6 August 1968 at Karlskronavarvet in Karlskrona, Sweden. County Governor Thure Andersson performed the christening, but numerous military and civilian honoratiores did not get to see any submarine leave the slipway. The water level was 30 cm below the average surface. In addition to County Governor Thure Andersson and his wife, among those present was the "Swedish-American of the Year" Admiral Arleigh Burke and his wife who made a detour to Karlskrona before continuing to Sofiero Palace to be received by King Gustaf VI Adolf. Among the guests were First Marshal of the Court Admiral Stig H:son Ericson, director (departementsråd) Benkt Dahlberg of the Ministry of Defence, the Chief of the Defence Staff Lieutenant General Stig Synnergren, and Sten Wåhlin, the director general of the Swedish Defence Materiel Administration. Kockums was represented by directors Nils Haldenborg, director Per Stenberg and director Karl-Gustaf Råwall.

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 Sjöhästen was sold to Singapore on 28 May 1999. She was never commissioned instead used as for spare parts.