The Srednyaya or S-class submarine (ru|Средняя|lit=medium), also called Stalinets class (ru|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 4000shp 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 530mm torpedo tubes, one 100mm deck gun, and one 45mm gun.[3]
S-56 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.
S-56 was laid down in Leningrad on 24 November 1936 before being shipped by rail to Vladivostok, where it was launched on 25 December 1939. The submarine was commissioned on 20 October 1941 with Grigory Shchedrin in command.[4]
For her service, the submarine was awarded with the Order of the Red Banner and the Guards badge.[5]
| + Ships sunk by S-56 | |||||
| Date | Ship | Flag | Tonnage | Notes | |
|---|---|---|---|---|---|
| 17 May 1943 | Eurostadt | tanker (torpedo) | |||
| 17 July 1943 | M-346 | minesweeper (torpedo) | |||
| 19 July 1943 | NKi-09/Alane | patrol vessel (torpedo) | |||
| 31 January 1944 | Heinrich Schulte | freighter (torpedo) | |||
| Total: | 7,191 GRT | ||||
During the attack against Eurostadt, another torpedo hit and damaged the German freighter Wartheland (3,676 GRT) but the ship was saved because the torpedo was a dud.