Gotland class submarine

The Gotland class submarines are modern diesel-electric submarines, designed and built by the Swedish navy. 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 several weeks. This capability had previously only been available with nuclear-powered submarines. The class has low acoustic signatures, extreme shock resistance and a competent combat system. It also has superior maneuverability due to the hull design and well-placed X rudder, enabling sharp turns and the ability to operate very close to the seabed. So far, only 3 have been built.

In 2004, the Swedish government leased the HMS Gotland for anti-submarine warfare exercises in the United States, which would last for one year. The lease was extended for another twelve months after the United States navy failed to detect the Gotland's presence, and having an entire carrier strike group "sunk" during the exercise. Even after two years of constant exercises, tests and radar/sonar developments, the United States still lacked the technology necessary to fight against the Gotland or similar submarines. The necessary sonar systems, anti-submarine torpedoes and electronic warfare systems still haven't been developed for the United States military yet, and it most likely won't before Sweden has finished the improved A26 submarine as a replacement for the Gotland.

Specifications
Type: Submarine.

Displacement when surfaced: 1,494 tonnes (1,470 long tons).

Displacement when submerged: 1,599 tonnes (1,574 long tons)

Length: 60.4 meters.

Beam: 6.2 meters.

Draft: 5.6 meters.

Propulsion: 2x Diesel-electric MTU engines and 2x Kockums v4-275R Stirling AIP units.

Speed when surfaced: 11 knots (20 km/h).

Speed when submerged: 20 knots (37 km/h).

Complement: 24 (18 officers and 6 seamen).

Sensors and processing systems: CSU 90-2 Integrated sonar sensor suite.

Armament: 4x 533mm torpedo tubes and 2x 400mm torpedo tubes.