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HSwMS Gotland Relaunched After Mid-Life Upgrade

After a comprehensive mid-life upgrade (MLU) to meet tomorrow’s naval challenges, HSwMS Gotland has been relaunched and is ready to start her sea trials.

Strategically important in a nation’s defence, submarines are designed to operate for decades in challenging environments whilst remaining adaptable given the advance of technology and future threats. To keep them at the cutting-edge of technology, Sweden’s Gotland-class submarines have received regular overhauls and upgrades during their operational life.

Due to this MLU, the Gotland submarine has capabilities that will be found in the next generation of Swedish submarines, the A26.   

“The relaunch of Gotland is an important milestone in the evolutionary development of Swedish submarines. After a comprehensive upgrade, integrating the latest generation of important systems such as the Stirling engine, modern sensors and new management functions, Gotland is almost a new submarine, ready to take on missions around the world,” says Gunnar Wieslander, Senior Vice President, head of business area Kockums at Saab.

The Gotland was designed and built by Kockums in Malmö in the early 1990’s and commissioned in 1996. The mid-life modification consists of upgrades of onboard systems and technology, sustaining the submarine’s operability, and ensuring service to Sweden beyond 2025.

The upgrade process entails many important systems, such as the Stirling Air Independent Propulsion (AIP). Sensors and management system are replaced with updated versions. Even the traditional optical periscope is replaced with a new optronic mast.

This updated version of the Gotland will pave the way for the most modern AIP submarine under production today: the A26 for the Royal Swedish Navy. More than 20 systems on-board the new Gotland-class will be implemented in the A26. The MLU of Gotland therefore contributes to the test and qualification of some of the innovative solutions to be implemented in the future Swedish A26 submarine class.

The relaunch ceremony of the Gotland took place in Karlskrona on June 20. Please visit for interviews, images and infographics regarding the relaunch.

Facts about the MLU of Gotland

Length overall                       62 m

Beam                                    6.2 m

Displacement                       1580 tons (surfaced)

Weapons                              Torpedoes, bow tubes, swim-out

Propulsion                            Single-shaft, diesel-electric and Stirling AIP

Endurance                            Weeks (submerged)

Hull                                       Single pressure hull, two pressure tight compartments

Crew                                     25

The Building Contract          Modifications of two submarines, verification incl. Set to Work (STW), Harbour Acceptance Test (HAT), Sea Acceptance Test (SAT), training, documentation, spares and upgrade of land-based Training Facility

                                             Delivery end of 2018 and 2019 respectively

Mid-life Upgrade                   Submarine is cut open in the mid-tank section, adding a new section including sea water cooling, fresh water cooling, water chiller units

Improved capabilities;          Stirling AIP MkIII, Masts, Sensors, Communication, Special Ops

New rules and regulations:  IMO, Security, Crew Comfort

End-of-life and obsolescence issues: Combat and Ship’s Management Systems

Experience based improvement

For further information, please contact:

Saab Press Centre,

+46 (0)734 180 018 

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Saab serves the global market with world-leading products, services and solutions within military defence and civil security. Saab has operations and employees on all continents around the world. Through innovative, collaborative and pragmatic thinking, Saab develops, adopts and improves new technology to meet customers’ changing needs.