Kockums upgrades Gotland class non-nuclear subs

23.09.2010 Sweden's defense material administration Forsvarets Materielverk (FMV) tied a contract with Kockums to modernize two Gotland class diesel/Stirling electric submarines. According to Defense Aerospace, the agreement implies upgrade of HMS Uppland and HMS Halland, and Gotland modernization option. Upgrade of HMS Halland will be completed in 2011.

During modernization the subs will be equipped with new navigational, display, and data exchange systems. It should be noted that the equipment to be installed on Gotland class subs will be functionally similar with systems installed in Sodermanland class diesel electric subs. Thus, all Swedish submarines will be capable to conduct effective data exchange.

It was reported in March 2010 that Swedish Navy ordered 5 sets of inertial navigation system from Northrop Grumman; such systems are based on ring laser gyroscopes. As expected, 4 sets will be installed in Swedish submarines, and the fifth one will be used for crew training. New gyroscopes will shift the obsolete rotating-wheel gyrocompasses.

Gotland class submarines are considered the world's best non-nuclear subs. During naval exercise held in 2000 in the Atlantic, Swedish sub Halland "scuppered" Spanish diesel electric sub, as well as French and American SSNs. In 2006-2007 Gotland submarine attended American exercise and, among other targets, "shipwrecked" Nimitz class aircraft carrier USS Ronald Reagan. At present, Kockums develops new Project A26 diesel/Stirling electric sub on the basis of Gotland project.

Gotland class submarines are capable to accelerate up to 20 knots by diesels and up to 5 knots by Stirling engines. Armament includes four 533-mm torpedo tubes and two 400-mm torpedo tubes.