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 208 feet 8 inches (63.6 m) overall, a beam of 24 feet (7.3 m) and a mean draught of 11 feet 10 inches (3.6 m). They displaced 768 long tons (780 t) on the surface and 960 long tons (980 t) submerged.[2] The S-class submarines had a crew of 40 officers and ratings. They had a diving depth of 300 feet (91.4 m).[3]
For surface running, the boats were powered by two 775-brake-horsepower (578 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 650-horsepower (485 kW) electric motor. They could reach 13.75 knots (25.47 km/h; 15.82 mph) on the surface and 10 knots (19 km/h; 12 mph) underwater.[4] On the surface, the second-batch boats had a range of 6,000 nautical miles (11,000 km; 6,900 mi) at 10 knots (19 km/h; 12 mph) and 64 nmi (119 km; 74 mi) at 2 knots (3.7 km/h; 2.3 mph) submerged.[3]
Seawolf was a member of the 2nd Submarine Flotilla at the onset of war. From 23–26 August 1939, the 2nd Submarine Flotilla deployed to its wartime bases at Dundee and Blyth.[6] On 6 October 1939, she attacked the German light cruiserNürnberg and the torpedo boatFalke in the Skagerrak, but none of the targets were hit. In April 1940, Seawolf sank the German merchant Hamm, and in November, claimed to have sunk the German merchant Bessheim. Bessheim was mined and sunk the previous day off Hammerfest, so Seawolf had probably attacked another merchant.
Akermann, Paul (2002). Encyclopaedia of British Submarines 1901–1955 (reprint of the 1989 ed.). Penzance, Cornwall: Periscope Publishing. ISBN1-904381-05-7.
Bagnasco, Erminio (1977). Submarines of World War Two. Annapolis, Maryland: Naval Institute Press. ISBN0-87021-962-6.
McCartney, Innes (2006). British Submarines 1939–1945. New Vanguard. Vol. 129. Oxford, UK: Osprey. ISBN1-84603-007-2.
Rohwer, Jürgen (2005). Chronology of the War at Sea 1939–1945: The Naval History of World War Two (Revised & Expanded ed.). Annapolis, Maryland: Naval Institute Press. ISBN1-59114-119-2.