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Sweden’s Deadly Stealthy Submarine Is Now Even Quieter

LINK TO ARTICLE A cornerstone of Gotland’s effectiveness in exercises with the U.S. Navy was its AIP propulsion. Indeed it was a major factor in why the Navy wanted to exercise against this specific boat. AIP meant that it could stay submerged for much longer than other non-nuclear boats. When Sweden loaned one of its AIP (Air Independent Power) submarines to the U.S. Navy, it made waves. HMS Gotland operated out of San Diego for over 2 years in the late 2000s, reputably ‘sinking’ the carrier USS Ronald Reagan (CVN-76) in an exercise. It wasn’t fast, but it was quiet, which is a valuable quality in underwater warfare. Now that submarine has been upgraded with an even stealthier propulsion system.

NOTES First-in-class submarine “Gotland” has been delivered to the Swedish Navy (Svenska Marinen) following a series of platform upgrades including a new AIP system and a combat system similar to the one set to be fitted aboard the next generation A26 submarine.

The upgrade process entailed many important systems, such as the Stirling air independent propulsion (AIP) system upgraded from Mk2 to the new Mk3, a complete new mast suite by Safran, Kongsberg’s SA9510S sonar and Exelis’ ES-3701 electronic warfare systems as well as new management, sensor and communication systems. The submarine’s hull was also extend via the addition of a 2 meters section.


The relaunch of HSwMS Uppland took place June 19, 2019. Two of the three Gotland-class submarines have now concluded comprehensive mid-life upgrades (MLU) and are equipped to face the challenges of tomorrow. There is an option for the modernization and upgrade of the third submarine of the class, HSwMS Halland.

According to Saab, the updated version of Gotland and her sister ship Uppland are paving the way for the most modern AIP submarine under production today: the Blekinge-class (A26) which is currently under producation at Saab Kockums facility in Karlskrona, in South Sweden.

More than 20 new systems on-board the new Gotland-class will be implemented in the the state of the art A26, which contributes to their de-risking for the A26. This also gives great training opportunities for the crew when they in the future deploy onboard the A26.

About Gotland-class SSK

HSwMS Gotland is the first of a group of 3 Gotland-class submarines. It is a defense submarine of the Swedish Navy. HSwMS Gotland was designed and built by Kockums in Malmö in the early 1990’s and commissioned in 1996.

HSwMS Gotland is a 60.7 meters long submarine with a displacement of 1 380 tons, mainly designed for submarine missions such as antiship/antisubmarine warfare, collecting of intelligence, forward surveillance, special operations, and mine-laying tasks.

Upgraded Gotland-class Main specifications:

  • Length: 62.7m
  • Beam: 6.2m
  • Draft: 5.6m
  • Propulsion: Two diesel-elctric MTU engines; 2 × Kockums v4-275R Stirling AIP units
  • Speed: 11 knots surfaced and 20 knots submerged
  • Crew: 32 maximum
  • Weapons: 4 × 533 mm Torpedo tubes; 2 × 400 mm Torpedo tubes; 48 × Externally Mounted Naval Mines
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