HMS Spur

The last 17 boats of the third batch were significantly modified from the earlier boats. They had a stronger hull, carried more fuel and their armament was revised. The submarines had a length of 217 feet (66.1 m) overall, a beam of 23 feet 9 inches (7.2 m) and a draft of 14 feet 1 inch (4.3 m). They displaced 814 long tons (827 t) on the surface and 990 long tons (1,010 t) submerged.[1] The S-class submarines had a crew of 48 officers and ratings. They had a diving depth of 350 feet (106.7 m).[2]

For surface running, the boats were powered by two 950-brake-horsepower (708 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 650-horsepower (485 kW) electric motor.[3] They could reach 14.75 knots (27.32 km/h; 16.97 mph) on the surface and 9 knots (17 km/h; 10 mph) underwater.[1] On the surface, the third batch boats had a range of 7,500 nautical miles (13,900 km; 8,600 mi) at 10 knots (19 km/h; 12 mph) and 120 nmi (220 km; 140 mi) at 3 knots (5.6 km/h; 3.5 mph) submerged.[2]

Spur was armed with six 21 inch (533 mm) torpedo tubes in the bow. She carried six reload torpedoes for a grand total of a dozen torpedoes. Twelve mines could be carried in lieu of the torpedoes. The boat was also equipped with a 4-inch (102 mm) deck gun.[1]

HMS Spur was built by Cammell Laird and launched on 17 November 1944. So far she has been the only ship of the Royal Navy to bear the name Spur. During her wartime career, Spur claimed to have sunk a total of eleven junks in the Strait of Malacca, during her service in the Far East.[4] The boat survived the Second World War and was sold to the Portuguese navy in November 1948, where she was renamed NRP Narval. She was broken up on 1 October 1969.

• Akermann, Paul (2002). Encyclopaedia of British Submarines 1901–1955 (reprint of the 1989 ed.). Penzance, Cornwall: Periscope Publishing. ISBN 1-904381-05-7.
• Bagnasco, Erminio (1977). Submarines of World War Two. Annapolis, Maryland: Naval Institute Press. ISBN 0-87021-962-6.
• Chesneau, Roger, ed. (1980). Conway's All the World's Fighting Ships 1922–1946. Greenwich, UK: Conway Maritime Press. ISBN 0-85177-146-7.
• Colledge, J. J.; Warlow, Ben (2006) [1969]. Ships of the Royal Navy: The Complete Record of all Fighting Ships of the Royal Navy (Rev. ed.). London: Chatham Publishing. ISBN 978-1-86176-281-8.
• McCartney, Innes (2006). British Submarines 1939–1945. New Vanguard. Vol. 129. Oxford, UK: Osprey. ISBN 1-84603-007-2.