Södermanland-class submarine
The Swedish Södermanland class of diesel-electric submarines consists of  and . These two submarines were originally launched as s in 1987 and 1990, and have been relaunched as a new class after extensive modernization in 2003 and 2004 by Kockums AB. The pressure hull had been cut in two after the sail and a  long new section with an air-independent propulsion system was inserted. It contains two Stirling engines which are coupled to electric generators and heated by burning diesel fuel with liquid oxygen stored in cryogenic tanks. The AIP system can provide electric energy to extend the submarine's submerged time from days to weeks. , Södermanland is planned to remain in service until at least 2024-25 when it was to be replaced by the future s. However, the Östergötland was decommissioned in 2021, and is in material reserve. Two submarines of similar design, known as the  are in service with the Republic of Singapore Navy. Units

References

External links
Kockums page about the Södermanland class
Kockums AIP Stirling system

Submarines of the Swedish Navy
Submarine classes of the Swedish Navy
Naval ships of Sweden