Finnish submarine Vesikko

History
Finland
Name:	Vesikko
Ordered:	9 October 1930
Builder:	Crichton-Vulcan
Laid down:	7 March 1931
Launched:	10 May 1933
Commissioned:	30 April 1934
In service:	19 January 1936
Out of service:	1946
Status:	Museum ship
General characteristics
Type:	Coastal submarine
Displacement:	254 t (250 long tons) surfaced 303 t (298 long tons) submerged 381 tonnes total,
Length:	40.90 m (134 ft 2 in) o/a 26.10 m (85 ft 8 in) pressure hull
Beam:	4.076 m (13 ft 4.5 in) 4.026 m (13 ft 2.5 in) pressure hull
Height:	8.18 m (26 ft 10 in)
Draft:	3.79 m (12 ft 5 in)
Propulsion:	Diesel-electric, 2 diesel engines each 350 PS (257 kW; 345 bhp) 2 double-acting electric motors each 180 PS (132 kW; 178 shp)
Speed:	13 knots (24 km/h; 15 mph) surfaced, 8 knots (15 km/h; 9.2 mph) submerged
Range:	1,350 nmi (2,500 km; 1,550 mi) at 8 knots surfaced, 40 nmi (74 km; 46 mi) at 4 knots (7.4 km/h; 4.6 mph) submerged
Test depth:	150
Complement:	4 officers, 8 non-commissioned officers, 4 enlisted
Sensors and processing systems:	2 × 6 Atlas Werke hydrophones, 1 receiver station (Gruppenhorchgerät)
Armament:	3 × 53.3 cm (21 in) torpedo tubes in the bow 5 torpedoes 1 × 20 mm (0.79 in)/60 Madsen AA gun 1 × 12.7 mm (1 in) machine gun 20 mines

Vesikko is a submarine (the single ship of her class), which was launched on 10 May 1933 at the Crichton-Vulcan dock in Turku. Until 1936 it was named by its manufacturing codename CV 707. Vesikko was ordered by a Dutch engineering company Ingenieurskantoor voor Scheepsbouw (a German front company) in 1930 as a commercial submarine prototype. Purchased by the Finnish before the war, she saw service in the Winter War and World War II, sinking the Soviet merchant ship Vyborg as her only victory. After the cease-fire with the Allies in 1944, Vesikko was retired. Finland was banned from operating submarines after the war and she was kept in storage until she was turned into a museum ship.

Vesikko was one of five submarines to serve in the Finnish Navy. The other four were the three larger Vetehinen-class boats Vetehinen, Vesihiisi, Iku-Turso and the small Saukko. The word "vesikko" is the Finnish name for the European mink.

Ingenieurskantoor voor Scheepsbouw (IvS), was a German front company in the Netherlands, established to secretly design a new German submarine fleet. According to the terms of the Versailles Peace Treaty after World War I, Germany was banned from building and operating submarines among other "offensive" weaponry. This resulted in moving the armaments' research to foreign countries. For example, German tanks and aircraft were tested and developed in the Soviet Union. Therefore, unlike the other submarines in the Finnish Navy, Vesikko was not part of the Naval Act. Instead, it was part of the secret rebuilding of the German Navy, the Reichsmarine.

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Wikipedia