Undervattensbåten No 2-class submarine

In 1900, the Swedish Navy sent Carl Richson to the United States, who was ordered to study submarines. After his return, he was inspired by USS Holland and designed HSwMS Hajen, Sweden's first submarine.^[1]: 11 After Hajen entered service in 1904, Richson revisited the design in 1909. He enlarged the superstructure and added an outer casing, which entered service as the Undervattensbåten No 2 class. Several years later, the design was again modified, with better engines and superstructure, to create the Laxen-class submarines.^{[1]: 131-132}

The class measured 26.72 metres (87 ft 8 in) in length with a beam of 3.61 metres (11 ft 10 in), draught of 3.00 metres (9 ft 10 in), and displaced 128 tons surfaced and 230 tons submerged. The complement consisted of 12 officers and crew. They were powered by a pair of Polar six-cylinder diesel engines and one electric motor that produced 420 brake horsepower (310 kW) and 200 horsepower (150 kW) respectively, which drove two propellers. This gave a maximum speed of 8.8 knots (16.3 km/h; 10.1 mph) on the surface and 6.6 knots (12.2 km/h; 7.6 mph) submerged. Armament consisted of a single 457-millimetre (18 in) torpedo tube mounted in the bow with a total capacity of three torpedoes.^[2]: 361

The submarines were built by Motala Verkstad and were all launched in 1909. After entering service, the submarines operated along the Swedish archipelago before they were decommissioned between 1929 and 1930.^{[2]: 361 [1]: 131-132}