A17 Vastergotland / Södermanland

The Västergötland (Type A 17) class was designed to carry out a variety of roles to provide defence against invasion including anti-surface warfare, mining, surveillance, anti-submarine warfare and insertion of special forces. The boats were built in the 1980s for the Royal Swedish Navy (RSwN) following awards of the design contract on 17 April 1978 and the construction contract on 8 December 1981 to Kockums, Malmö. Kockums, which is part of ThyssenKrupp Marine Systems, built the midship section and carried out final assembly while Karlskrona built the bow and stern sections.

Four boats were commissioned into the RSwN: Västergötland (November 1987), Hälsingland (October 1988), Södermanland (April 1989) and Östergötland (January 1990). The first two boats were retired early due to defense cuts.

Södermanland and Östergötland were retained in service after undergoing a mid-life refit and are known as the Södermanland class. Södermanland began refit at Kockums in late 2000 and was relaunched on 8 September 2003 for six months of sea trials and she returned to service in mid-2004. Improvements included: installation of Air Independent Propulsion (Stirling Mk 3 AIP), requiring the insertion of a 12 m section into the pressure hull, installation of a pressurised diver's lock-out in the base of the sail to facilitate special forces operations, installation of a new climate control system incorporating cooling equipment featuring freon compressors. The climate control measures were intended to enable international operations in warmer waters than those of the Baltic Sea. Following a similar refit, Östergötland was relaunched on 3 September 2004 and returned to service in 2005.

The upgrade of the Södermanland class provided two practically new submarines, capable of operating for the next twenty years with no further modernisation. The submarines were lengthened by inserting a Stirling AIP section. This section, fully fitted and equipped prior to installation, contains several Stirling units, liquid oxygen tanks and electrical equipment. Consequently, all operational submarines in the Swedish fleet now have Stirling air-independent propulsion - unique among navies equipped with conventional (non-nuclear) submarines. An important aspect of the Södermanland class upgrade programme is that the vessels are now equipped for international peacekeeping missions in warmer and more saline waters. This has involved fitting completely new refrigeration systems and climate control system. The Command, Control, Computer, Communication and Intelligence systems (C4I) of the Södermanland class have been upgraded to the latest standards and the boats' stealth capabilities are being further refined. The submarines have also been equipped with a new airlock for divers.

The two Södermanland (previously Västergötland) (Type A-17) boats built by Kockums for the Swedish Navy have been designed to carry out a variety of roles to provide defence against invasion. Among the missions envisaged for the boats are attack, mining, surveillance, anti-submarine and interjection of Special Forces. The two-deck single-hull design features two watertight compartments divided by a centre watertight bulkhead. The pressure hull is of circular cross-section ending in truncated cones. Fore and aft the hull extends into ballast tanks. The forward compartment houses accommodation, stores, communications room and control room on the upper level, with weapons handling and nine torpedo tubes (six conventional 533 mm with 12 torpedoes and three 400 mm tubes with six weapons), forward battery section and auxiliary machinery on the lower deck.

Immediately aft of the watertight bulkhead is a cylindrical tank section with a passage aft and an escape lock, which connects to a rescue vehicle or bell. The after section houses the electrical control centre with the aft battery section, diesel generators and propulsion motor on the deck below. Manoeuvrability is exercised through an X-configuration rudder/after hydroplane design. The boats carry a comprehensive range of sensors including periscopes, Terma radar, the American EDO RSS AR-700-S5 ESM, and a wide range of ATLAS Elektronik sonars, including the CSU-83. Sonar arrays are mounted on and under the casing. The boats are equipped with an Ericsson IPS-17 weapons control system developed from the NIBS system fitted in the Näcken class.

In May 2005 Kockums signed a contract with Singapore's Ministry of Defence to supply two Västergötland-class submarines to the Republic of Singapore Navy. Currently in service with the Royal Swedish Navy (RSwN), the submarines would be transferred to Singapore on completion of the modernization and conversion for operation in tropical waters. The contract also includes a logistics package and training for the crews. Training will be conducted by the Swedish Navy in Karlskrona, along the lines adopted in conjunction with a previous order for submarines for Singapore.

Kockums has a valuable relationship with Singapore, having previously supplied Mine hunters and the current Challenger-class submarines to the Singapore Navy. We are naturally delighted and honoured to be entrusted with supplying the two submarines to Singapore. I am confident that the two Västergötland-class submarines, when handed over, will enhance the Singapore Navy's submarine capability, says Kockums´ CEO Martin Hagbyhn, commenting on the news. Kockums, which has an office in Singapore, has supplied submarines, mine hunters (MCMVs) and mine-clearance systems to the Republic of Singapore Navy (RSN) since 1991.

Among other improvements, the Sodermanland class submarines have a stretched hull compared to Vastergotland class. In November 1999 the Swedish Defence Materiel Administration (FMV) has signed a contract with Kockums which involves a general upgrade, modernisation and life prolongation of two Västergötland class submarines. The total sum of this contract is some 600 million SEK. The contract included the installation of the latest Stirling machinery (MK 3), a power generation system which is independent of air supply. The advanced Stirling system allows the submarine to operate submerged considerably longer time than today's conventional submarines. This means, that the two Västergötland class submarines will have the capability to operate against more advanced technical threats of the future. Following the modernisation of these two Västergötland class submarines, the Swedish Armed Forces will operate five submarines, including the recently delivered three Gotland class submarines, which are all equipped with Stirling machinery.