The Royal Swedish Navy's submarine flotilla consists of five submarines based at Muskö. The Swedish Navy was the first to operate vessels using an air-independent propulsion (AIP) system based on the Stirling engine. Three Gotland-class units are equipped with AIP, an additional two Västergötland-class vessels have been retrofitted with the system and renamed Södermanland-class.[1]

Plans to develop a new submarine type, the Viking, were terminated after Denmark and Norway withdrew from the development program. However, Sweden's Defense Materiel Administration (FMV) has been tasked with initiating the preliminary planning for an even more modern submarine, currently designated the A26 class, for the future. The design phase is scheduled to begin in 2007.[2] Kockums is participating in developing the new vessel. Kockums Vice President of Communications Kjell Göthe has said that the company is seeking foreign partners to share the development costs and is in discussions with three potential partner countries.[11]

According to the A26 concept, the submarine will be based on a modular design to make possible the rapid reformatting of the vessel for varying tasks. Given Sweden's small fleet, it is critical that such operations can be accomplished in a minimal amount of time. The A26 will include a large bow section from which unmanned underwater vehicles (UUVs) can be launched, can be used to transport special forces, and can be used for reconnaissance, mine detection, mine laying, and underwater mapping, as well as warfighting. Like Sweden's current fleet, the A26 will be equipped with Stirling AIP. However, it would have enhanced stealth technology, better sensors, and would not be as dependent on port facilities. Kockums is investigating several ways to improve communications with onshore command without giving up the submarine's position, including the possible use of UUVs for communications purposes or new antennas on the submarine.[3]

Sweden's submarines are considered an important defense asset. The submarine force's area of operation has recently been expanded from its original task of countering the threat of Soviet invasion in the Baltic Sea region. Sweden's submarines have begun to participate in multinational rapid reaction exercises acting in waters that range from the North Sea, the Atlantic, and the Bay of Biscay to the Mediterranean with new tasks focusing on reconnaissance, intelligence gathering, and surveillance.[1] The Viking next-generation submarines were designed to enhance these capabilities, as they featured increased endurance and interoperability with other naval branches.[4] However, with the withdrawal of Denmark and Norway from the Viking program, it is not clear that Sweden will be able to find new partners for the program, or fund the design, construction, and operation of these new boats on its own.

In May 2005, the Gotland was leased to the U.S. Navy for one year, complete with a Swedish crew. The Gotland will initially be based in San Diego, where the U.S. Navy will practice joint maneuvers with the stealthy AIP-equipped diesel submarine.[5] According to the Swedish newspaper Blekinge Läns Tidning, U.S. interest in the Gotland class was aroused during joint naval exercises when the U.S. Navy was unable to track the Swedish submarine.[6]

During its first year in the United States, the Gotland is scheduled to conduct up to 160 training days at sea, supporting strike groups, individual ships and rescue submarines, as well as participate in testing and development of new equipment.[7] The Gotland regularly uses its diesel engines only when entering or exiting port, going on two-week-plus "silent" patrols using its Stirling AIP engines exclusively.[8] As of March 2006, the U.S. Navy was reportedly in talks with Sweden on extending the lease for one to two more years.[8,10] Reportedly, during a Joint Task Force Exercise on December 6-16, 2005, with the USS Ronald Reagan Carrier Strike Group off the coast of Southern California, the Gotland managed to take several pictures of the Ronald Reagan from close quarters, indicating a "strike" on the aircraft carrier.[9] As Gotland's Lieutenant Commander Jan Westas says, the U.S. ASW forces "have had a very difficult time finding us."[8] To date, the exercises have been carried out in deep water. It is expected that exercises with the Gotland in coastal waters will prove even more challenging to U.S. ASW.[8]

Sources:
[1] Bo Rask, "The Swedish submarine force in the future," Naval Forces, Vol. 24, No. 3 (2003), pp. 85; in ProQuest Information and Learning Company, http://proquest.umi.com.
[2] "Submarine Development," FMV Annual Report 2005, Swedish Defence Materiel Administration, www.fmv.se.
[3] Magnus Forsberg, "Ledningsplattform med tentakler," Protec, No. 1, 2006, Swedish Defence Materiel Administration, www.fmv.se.
[4] Interview with the Director General of the Swedish Defense Materiel Administration, Brigitta Bohlin, by Wolfgang Legien, "Quality provider for the Swedish Navy," Naval Forces, Vol. 24, No. 1 (2003), pp. 75-78; in ProQuest Information and Learning Company, http://proquest.umi.com.
[5] "RSwN submarine HMS Gotland on lease to US Navy for twelve months," May 31, 2005, Kockums, www.kockums.se.
[6] "USA to lease Gotland-class sub," November 5, 2004, Kockums, www.kockums.se.
[7] "Swedish Submarine Continues to Play Important Role in Joint Training," December 20, 2005, Navy Newsstand, www.news.navy.mil.
[8]Norman Polmar, "Back to the Future," United States Naval Institute Proceedings (Annapolis: March 2006), pp. 20-26; in ProQuest Information and Learning Company, http://proquest.umi.com.
[9] "Svensk Ubåt 'sänkte' USA:s hangarfartyg," Allehanda, January 16, 2006, www.allehanda.se.
[10] "USA vill fortsätta jaga svensk ubåt," Svenska Dagbladet, April 18, 2006, www.svd.se.
[11] "Kockums utvecklar ny ubåt åt försvaret," NyTeknik Website, June 1, 2005.