Soviet submarine S-2

S-2 was the second S-class submarine of the Soviet Navy. In early 1940, it entered Swedish territorial waters in the Sea of Åland where it hit a Swedish naval mine, and sank on January 2, 1940, with the loss of all 50 crew members.

Design
The Srednyaya or S-class submarine (Средняя), also called the Stalinets-class (Сталинец), was an ocean-going diesel electric attack submarine. Its pressure hull had seven compartments, and the Series IX submarine's displacement was 840 t while on the surface and 1070 t while submerged. It had a length of 77.8 m, a beam of 6.4 m, and a draft of 4 m. It had two diesel engines to power it on the surface and two electric motors for when it was submerged, providing 4000 shp and 1100 shp, respectively, to the two propeller shafts. This gave it a speed of 19.5 kn on the surface and 9 kn while underwater, and the submarine had a range of 9500 nmi. Its test depth was 80 m, and as armament it had six 530 mm torpedo tubes, one 100 mm deck gun, and one 45 mm gun.

S-2 was one of three Series IX boats, along with SOVIET SUBMARINE S-1 and SOVIET SUBMARINE S-3. The original design was made by German engineers at NV Ingenieurskantoor voor Scheepsbouw, the Dutch subsidiary of AG Weser, and later boats were modified by the Soviets to take into account the manufacturing capabilities available in the Soviet Union. After examining the German prototype submarine E-1 in 1932 and 1933, Soviet engineers decided to purchase its design for the Soviet Navy with some changes, increasing its size, range, and armament. E-1 became the basis for the first three S-class submarines, the Series IX boats, which were built in Leningrad using some German components.

Wreck discovery
A search for the submarine wreck was begun in April 1999 by a team of divers from Sweden and Åland. According to the Military Archives of Sweden, the submarine hit the mine in Swedish territorial waters, but the Finnish archives specify the sinking occurred on Finnish territorial waters. The uncertainty of position necessitated a prolonged search. The diving team finally discovered the wreck inside Swedish territorial waters. One member of the diving team, Ingvald Eckerman, is a grandson of J. A. Eckerman who, as the lighthouse-keeper of the lighthouse at Märket, witnessed the submarine sinking in 1940.

The wreck was emptied of munitions during the summer of 2012.