Näcken-class submarine

The Näcken-class submarines, also known as the A14 type, were built for the Swedish Navy in the late 1970s. The boats were authorised in 1972 and the programme was completed in 1980 . All boats were built by Kockums in Karlskrona. The boats had a teardrop hull and diving depth was 150 metres (490 ft). Between 1987 and 1988 Näcken was cut in half and an 8-metre (26 ft) long hull section containing a prototype Air-independent propulsion (AIP) using a closed cycle Stirling engine was installed between the aft battery/propulsion & power control room and the engine/motor room. This technology increased underwater endurance to 14 days and has been adopted in subsequent Swedish submarines.

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