Västergötland-class Patrol Submarine

The Västergötland-class Patrol Submarines are a class of six submarines (four the in Swedish Navy and two in the Republic of Singapore Navy). In the early 2000s, the four submarines underwent comprehensive refits, including the insertion of a new hull section with an Air-independent propulsion system equipped with Stirling engines. In the mid-2000s, the Singapore Navy built a version of the subs that were acclimatized for use in tropical waters named the Archer-class.

Original Specifications

 * Type: Diesel-Electric Patrol Submarine
 * Service Period: 1987-Present
 * Characteristics
 * Length: 159 feet 1 inch (48.49 meters)
 * Beam: 20 feet (6.1 meters)
 * Draft: 18 feet 4 inches (5.59 meters
 * Displacement: 1,070 tons (Surfaced); 1,150 tons (Submerged)
 * Crew: 24
 * Propulsion: 2 x Hedmora V12A/15, 1 x Jeumont-Schneider electric motor
 * Speed: Surfaced - 11 knots (20.37 km/hr); Submerged - 20 knots (37.4 km/hr)
 * Sensor Suite:
 * CSU 90-2 Integrated sonar sensor suite
 * Armament
 * 6 x 533mm torpedo tubes
 * 3 x 400mm torpedo tubes

Refit Specifications

 * Type: AIP-equipped Diesel-Electric Submarine
 * Service Period: 2004-Present
 * Characteristics
 * Length: 198 feet 6 inches (60.5 meters)
 * Beam: 20 feet (6.1 meters)
 * Draft: 18 feet 4 inches (5.59 meters)
 * Displacement: 1,400 tons (Surfaced); 1,500 tons (Submerged)
 * Crew: 24
 * Propulsion: 2 x Hedemora diesel-electric engines, 2 x Kockums v4-275R Sterling AIP units
 * Speed: 20 knots (37.04 km/h)
 * Sensor Suite:
 * CSU 90-2 Integrated sonar sensor suite
 * Armament
 * 6 x 533mm torpedo tubes
 * 3 x 400mm torpedo tubes

Archer-class Specifications

 * Type: AIP equipped Diesel-Electric Patrol Submarine
 * Service Period: 2011-Present
 * Characteristics
 * Length: 198 feet 6 inches (60.5 meters)
 * Beam: 20 feet (6.1 meters)
 * Draft: 18 feet 4 inches (5.59 meters)
 * Displacement: 1,400 tons (Surfaced); 1,500 tons (Submerged)
 * Crew: 28
 * Propulsion: 2 x Hedemora diesel-electric engines, 2 x Kockums v4-275R Sterling AIP units
 * Speed: Surfaced - 8 knots (14.82 km/hr); Submerged - 15 knots (27.78 km/hr
 * Sensor Suite: FAS
 * Armament
 * 6 x 533mm torpedo tubes
 * 3 x 400mm torpedo tubes

Swedish Navy

 * HSwMS Västergötland (S66)
 * HSwMS Hälsingland (S67)
 * HSwMS Södermanland (S68)
 * HSwMS Östergötland (S69)

Republic of Singapore Navy

 * RSS Archer (S05)
 * RSS Swordsman (S06)