Gotland-class submarine explained

The Gotland-class submarines of the Swedish Navy are modern diesel-electric submarines, which were designed and built by the Kockums shipyard in Sweden. They are the first submarines in the world to feature a Stirling engine air-independent propulsion (AIP) system, which extends their underwater endurance from a few days to weeks.[1] This capability had previously only been available with nuclear-powered submarines.

Features

As of 2008, the Gotland-class attack submarine is one of the most modern submarines of the Swedish Navy in service, mainly designed for submarine missions such as antiship/antisubmarine warfare, collecting of intelligence (communications intelligence (COMINT), electronic signals intelligence (ELINT)), forward surveillance, special operations, and mine-laying tasks.

On the water surface, the submarine is powered by two sets of MTU engines. While submerged, the Kockums-built Stirling engine AIP system is used to drive a 75shpNaNshp generator for either propulsion or charging the batteries. A Stirling engine is particularly well suited for a submarine because the engine is nearly silent and can use the surrounding seawater as a heat sink to increase efficiency. Submerged endurance is dependent on the amount of liquid oxygen stored onboard and is described as "weeks". The class is characterized by its low acoustic signatures, extreme shock resistance, and a competent combat system.

Kockums touts extreme manoeuvrability for this class due to the hull design and a well-placed X rudder. The X rudder provides four control surfaces, along with two mounted on the sail, which enables sharp turns and the ability to operate very close to the seabed. Ship automation and computerized steering allow a single operator to steer the submarine in depth and course, which also results in a smaller crew complement, leading to good accommodation standards and low operating costs.[2]

The class has many features that enhance stealth, helping it to remain undetected. All shipboard machinery is isolated and mounted on rubber dampeners to reduce vibrations and noises; a hydrodynamic hull design reduces noise, infrared signature, and active sonar response. Its magnetic signature is counteracted by 27 independent electromagnets, short-circuiting extremely low frequency (ELF) electrical fields. Various hull coatings reduce active sonar response, and the mast is coated with radar-absorbent material. Combined with the near-silent operation of the Stirling generator and slow-turning propeller to prevent cavitation, the boats are very difficult to detect underwater, especially in their normal area of operations, the Baltic Sea.[2]

Units

Ship nameLaid downLaunchedCommissionedServiceStatusBadge
HSwMS Gotland (Gtd)10 October 19922 February 199519961st Submarine FlotillaActive
14 January 19948 February 199519961st Submarine FlotillaActive
21 October 199427 September 199619961st Submarine FlotillaActive

Deployments

After being refitted and upgraded to sustain the higher temperatures of tropical water,[3] HSwMS Halland took part in a multi-national exercise in the Mediterranean from September 16, 2000. Allegedly, there she remained undetected while still recording many of her friendly adversaries, attracting interest from the participating countries. In early November of the same year, she participated in a NATO "blue-water" exercise in the Atlantic. There, she reportedly won a victory in a mock "duel" with Spanish naval units, and then the same in a similar duel against a French SSN, a nuclear-powered attack submarine. She also defeated an American SSN, the USS Houston.

Secondment to United States Navy

In 2004, the Swedish government received a request from the United States to lease HSwMS Gotland  - Swedish-flagged, commanded and manned, for one year for use in antisubmarine warfare exercises. The Swedish government granted this request in October 2004, with both navies signing a memorandum of understanding on 21 March 2005.[4] [5] The lease was extended for another 12 months in 2006.[6] [7] [8] In July 2007, HSwMS Gotland departed San Diego for Sweden.[9]

In 2005, HSwMS Gotland managed to snap several pictures of during a wargaming exercise in the Pacific Ocean, demonstrating that it was in a position to sink the aircraft carrier.[10] The exercise was conducted to evaluate the effectiveness of the US fleet against diesel-electric submarines, which some have noted as severely lacking.[11] [12] In 2001, during the exercise JTFEX 01-2 in the Caribbean Sea, the German U24 of the conventional 206 diesel-electric class "sank" the carrier Enterprise by firing flares and taking a photograph through its periscope.[13]

Overhaul

Initial discussions

In March 2013, Kockums received an initial order for an overhaul for two of the Gotland-class submarines. The overhaul was expected to be completed by 2017. With these upgrades, the submarines would be able to remain in active duty until after 2025.[14] On 2 April 2014, the Swedish defence minister, insisting on the importance of submarines to the security of Sweden, announced the Government's intent to upgrade two of the Gotland-class vessels, as well as purchase two new "stealth" submarines of another type.[15]

Mid-life upgrade contract

Negotiations concluded on 30 June 2015 with the signature of a contract between Sweden's Defense Material Administration (FMV) and Saab Kockums. In addition to the construction of two new Type 26 A SSKs, the contract provides for a mid-life upgrade of HSwMS Gotland and her sister ship HSwMS Uppland, for SEK 2.1 billion. Gotland is expected to return to the FMV in late 2018 and Uppland in late 2019, following a series of platform and combat systems upgrades. Gotland returned to active duty in June 2018 after receiving modification for over 20 systems. Same systems will also be included on the new A26 submarines.[16] relaunched in June 2019[17] and was delivered to the Navy in December 2020.[18] In March 2022 FMV and SAAB signed a contract for MLU of HMS Halland[19]

See also

External links

Notes and References

  1. Web site: The Gotland class submarine - submerged several weeks . Kockums . 2008-04-06 . 2011-04-25 . https://web.archive.org/web/20110425220545/http://www.kockums.se/en/products-services/submarines/gotland-class/ . dead .
  2. Web site: Kockums Promotional . Naval Technology . 2011-11-21.
  3. [Kockums]
  4. Web site: US Navy Leasing Swedish Gotland-Class Submarine . Deagel . 2004-11-05.
  5. U.S., Swedish Navies Sign Agreement to Bilaterally Train on State-of-the-Art Sub . United States Navy . 2005-03-23 . dead . https://web.archive.org/web/20070819041151/http://www.news.navy.mil/search/display.asp?story_id=17621 . 2007-08-19 .
  6. News: US Navy to continue hunt for Swedish sub . The Local . 2006-04-18 . 2006-07-21 . dead . https://web.archive.org/web/20090329115136/http://www.thelocal.se/article.php?ID=3574 . 2009-03-29 .
  7. Gotland extends US stay for another year . Kockums AB . 2006-06-13 . 2006-07-21 . dead . https://web.archive.org/web/20061001063127/http://www.kockums.se/News/060613gotland.html . 2006-10-01 .
  8. HMS Gotland's Stirling propulsion system basis of success in the USA. Kockums AB. 2007-05-09. 2009-06-16. 2010-09-24. https://web.archive.org/web/20100924182055/http://www.kockums.se/news/070509gotland.html. dead.
  9. Web site: SSK Gotland Class (Type A19) Attack Submarine, Sweden . Naval Technology . 2008-04-06.
  10. News: Pentagon: New Class Of Silent Submarines Poses Threat . https://web.archive.org/web/20071116120858/http://www.knbc.com/news/10116514/detail.html . dead . 2007-11-16 . KNBC . 2006-10-19 . 2006-07-21.
  11. Polmar . Norman . March 2006 . Back to the Future . U.S. Naval Institute Proceedings . 132 . 3 . 22 - 23 . 0041-798X.
  12. Web site: US Navy Struggles to Recapture, Keep ASW Proficiency . The Nav Log . 2008-04-06 . https://web.archive.org/web/20090202192615/http://navlog.org/asw_feb06.html . 2009-02-02 . dead .
  13. News: Deutsches U-Boot fordert US-Marine heraus . t-online . 2013-01-06 . 2020-12-18 . de.
  14. Web site: Monica . Kleja . Kockums får stor ubåtsorder . sv . Kockums gets big submarine orders . . 2012-10-05 . 2017-09-20 . 2016-03-04 . https://web.archive.org/web/20160304031537/http://www.nyteknik.se/nyheter/fordon_motor/fartyg/article3553829.ece . dead .
  15. News: Mats . Knutson . Love . Benigh . Regeringen stoppar planerad ubåtsaffär . sv . The government stops the planned submarine business . . 2014-04-02 . 2017-09-20.
  16. Web site: Sjösättning av modifierad ubåt. Hans. Ivansson. www.fmv.se. 2018-06-20. 2018-06-21. https://web.archive.org/web/20180621015902/http://www.fmv.se/sv/Nyheter-och-press/Nyheter-fran-FMV/Sjosattning-av-modifierad-ubat/. dead.
  17. Web site: Second Gotland-class Submarine HMS Uppland Relaunched following MLU by Saab. www.navalnews.com. 21 June 2019.
  18. Web site: Saab Delivers Modernized Gotland-class Submarine – SeaWaves Magazine.
  19. Saab Signs Contract for Mid-Life Upgrade of the Third Gotland-class Submarine . https://web.archive.org/web/20220318223321/https://www.saab.com/newsroom/press-releases/2022/saab-signs-contract-for-mid-life-upgrade-of-the-third-gotland-class-submarine . 2022-03-18 . bot: unknown . 2022-03-19 .