S-7 was an S-class submarine (Series IX-bis) of the Soviet Navy. Her keel was laid down by Krasnoye Sormovo in Gorkiy on 14 December 1936. She was launched on 5 April 1937 and commissioned on 30 June 1940 in the Baltic Fleet. During World War II, the submarine was under the command of Captain Sergei Prokofievich Lisin and took part in the Soviet submarine Baltic Sea campaign in 1942. S-7 scored victories, but was sunk in action.
The Srednyaya or S-class submarine (Russian: Средняя|lit=medium), also called the Stalinets class (Russian: Сталинец|lit=follower of Stalin), was an ocean-going diesel electric attack submarine. Its pressure hull had seven compartments, and the Series IX-bis submarine's displacement was 856t while on the surface and 1090t while submerged. It had a length of 77.8m (255.2feet), a beam of 6.4m (21feet), and a draft of 4m (13feet). It had two diesel engines to power it on the surface and two electric motors for when it was submerged, providing and, respectively, to the two propeller shafts. This gave it a speed of 18.85kn on the surface and 8.8kn while underwater, and the submarine had a range of 9500nmi. Its test depth was 80m (260feet), and as armament it had six 530NaN torpedo tubes, one 100mm deck gun, and one 45mm gun.[1]
S-7 was part of the Series IX-bis, which was a modification of the original three boats of the S-class, the Series IX. The main difference between them was the replacement of German components used in Series IX with Soviet equivalents that could be manufactured domestically.
The submarine made all her victories in summer 1942, having some success against the German-Swedish iron ore shipping lines (the main target of 1942 Soviet submarine campaign).
| Date | Ship | Flag | Tonnage | Notes | |
|---|---|---|---|---|---|
| 9 July 1942 | Margareta |  | freighter (torpedo) | ||
| 11 July 1942 | Lulea | | freighter (torpedo) | ||
| 30 July 1942 | Kathe | freighter (torpedo) | |||
| 5 August 1942 | Pohjanlahti |  | freighter (deck gun) | ||
| Total: | 9,164 GRT | ||||
On 27 July 1942 S-7 also attacked the German merchant Ellen Larsen (1,938 GRT): the torpedoes missed and S-7 opened fire with her gun. As result the merchant was driven ashore.
While attempting a new campaign (after the successful summer one), S-7 was attacked, torpedoed and sunk by the .
Four crewmembers were saved and captured, including the commander Lisin. Commander Lisin was believed killed in action and was awarded post-mortem the distinction, Hero of the Soviet Union. Once Finland signed an armistice with the Allies in 1944, Lisin was freed and was sent by the Soviets to an NKVD special camp. However accusations against him were dropped (he kept the title of Hero) and became a military instructor at an officer school.[3]
In July 1998, the wreck of S-7 was found. The official data of war archives alleges that S-7 was torpedoed in Finnish waters, but the submarine was found in Swedish territorial waters – east of Söderarm in Stockholm's northern archipelago.[4]