S-2 was the designation of a Stalinets class submarine

Soviet S class submarine

The S-class or Srednyaya submarines were part of the Soviet Navy's underwater fleet during World War II. Unofficially nicknamed Stalinets , boats of this class were the most successful and achieved the most significant victories among all Soviet submarines...

 of the Soviet Navy

Soviet Navy

The Soviet Navy was the naval arm of the Soviet Armed Forces. Often referred to as the Red Fleet, the Soviet Navy would have played an instrumental role in a Warsaw Pact war with NATO, where it would have attempted to prevent naval convoys from bringing reinforcements across the Atlantic Ocean...

. In early 1940, it entered Swedish

Sweden

Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

 territorial waters

Territorial waters

Territorial waters, or a territorial sea, as defined by the 1982 United Nations Convention on the Law of the Sea, is a belt of coastal waters extending at most from the baseline of a coastal state...

 in the Sea of Åland

Sea of Åland

The Sea of Åland is the waters located in the southern Gulf of Bothnia, between the Åland islands and the Swedish mainland. The sea connects Kvarken and the Bothnian Sea with the Baltic Sea proper. The seas are often choppy here. The narrowest part is named Södra Kvarken or South Kvarken....

. There it hit a Swedish naval mine

Naval mine

A naval mine is a self-contained explosive device placed in water to destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, an enemy vessel...

, and sank on January 2, 1940. All of the 50 crewmembers on board perished.

Wreck discovery

A search for the submarine wreck

Wreck

Wreck may refer to:* Wreck, a ceremony of initiation into the 40 et 8 club* Wreck , an American indie rock band* A collision of an automobile, aircraft or other vehicle* Shipwreck, the remains of a ship after a crisis at sea...

 was begun in April 1999 by a team of divers from Sweden and Åland. According to the Military Archives of Sweden

Military Archives of Sweden

The Military Archives of Sweden is the part of the National Archives of Sweden that keeps archives related to agencies sorting under the Ministry of Defence...

, the submarine encountered the mine on Swedish territorial waters, but the Finnish

Finland

Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...

 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

Lighthouse

A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....

 at Märket

Märket

Märket is a small 3.3 hectares uninhabited skerry in the Baltic Sea between Sweden and Finland , which has been divided between two sovereignties since the Treaty of Fredrikshamn of 1809 defined the border between Sweden and Russian Empire as going through the middle of the island...

, witnessed the submarine sinking in 1940.