The second batch of S-class submarines were designed as slightly improved and enlarged versions of the earlier boats of the class and were intended to operate in the North and Baltic Seas.[1] The submarines had a length of 208feet overall, a beam of 24feet and a mean draught of 11feet. They displaced 768LT on the surface and 960LT submerged.[2] The S-class submarines had a crew of 40 officers and ratings. They had a diving depth of 300feet.[3]
For surface running, the boats were powered by two 7750NaN0 diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 650hp electric motor. They could reach 13.75kn on the surface and underwater.[4] On the surface, the second-batch boats had a range of 6000nmi at and 64nmi at submerged.[3]
The S-class boats were armed with six 21-inch (533 mm) torpedo tubes in the bow. They carried six reload torpedoes for a total of a dozen torpedoes. They were also armed with a 3-inch (76 mm) deck gun.[2]
Ordered on 16 June 1933, Snapper was laid down on 18 September 1933 at HM Dockyard, Chatham and was launched on 25 October 1934. The boat was completed on 14 June 1935.[5]
Snapper spent most of her career in home waters. She was mistakenly attacked by a British aircraft when returning to Harwich after a patrol in the North Sea. Although suffering a direct hit, Snapper escaped damage. She went on to sink the small German oil tanker, the German merchant Florida, the German auxiliary minesweepers M 1701 / H. M. Behrens and M 1702 / Carsten Janssen, the German armed trawler V 1107 / Portland and the Norwegian merchant Cygnus. She also attacked the German armed merchant cruiser, but the torpedoes missed their target.[6]
She left the Clyde on 29 January 1941 to patrol in the Bay of Biscay. She should have arrived in her patrol area on 1 February. She was ordered to remain on station until 10 February and then to return with her escort. Snapper failed to make the rendezvous with the escort and was not heard from again. It is believed that she met her fate through a mine or that she was mortally damaged by a minesweeper which attacked a submarine in Snappers area on 11 February, although Snapper should have been out of the area by then.[7] Other sources report that the S-class submarine was depth charged and sunk in the Bay of Biscay south west of Ouessant, Finistère, France (47.4167°N -52°W) by the German minesweepers, and with the loss of all 41 crew.[8] [9]