All Swedish Navy submarines will soon be equipped with Stirling Air Independent Propulsion (AIP) systems, which substantially enhances the operational efficiency of conventional (non-nuclear) submarines.
The Swedish Navy submarine HMS Södermanland has recently undergone a refit and been upgraded with the Stirling propulsion system by Kockums, in Karlskrona. And in the autumn, the next Västergötland class submarine should be ready to put to sea, following the launch and sea trials of HMS Östergötland.
The Stirling propulsion system enables a conventional submarine to remain submerged for several weeks, minimizing the risk of detection and greatly increasing its stealth capabilities.
With the completion of the HMS Södermanland and HMS Östergötland upgrades, all Swedish Navy submarines currently in service will be equipped with Stirling propulsion systems. In naval circles, this has led to the coining of a new concept: the “Royal Stirling Navy”.
The Västergötland class submarines have been lengthened by twelve meters. Some claim that this makes HMS Södermanland Sweden’s longest submarine, making it even longer (if only a few centimeters) than HMS Gotland. Needless to say, this is now the subject of intense internal (partisan!) debate.