HMS L56

L52 and its successors were modified to maximise the number of 21-inch (53.3 cm) torpedoes carried in the bow. The submarine had a length of 235 feet (71.6 m) overall, a beam of 23 feet 6 inches (7.2 m) and a mean draft of 13 feet 2 inches (4.0 m).[1] They displaced 960 long tons (980 t) on the surface and 1,150 long tons (1,170 t) submerged. The L-class submarines had a crew of 44 officers and ratings.[2] They had a diving depth of 150 feet (45.7 m).[3]

For surface running, the boats were powered by two 12-cylinder Vickers[4] 1,200-brake-horsepower (895 kW) diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 600-horsepower (447 kW) electric motor. They could reach 17 knots (31 km/h; 20 mph) on the surface and 10.5 knots (19.4 km/h; 12.1 mph) underwater. On the surface, the L class had a range of 4,200 nautical miles (7,800 km; 4,800 mi) at 10 knots (19 km/h; 12 mph).[1]

The boats were armed with six 21-inch torpedo tubes in the bow. They carried eight reload torpedoes for a grand total of a dozen torpedoes.[5] They were also armed with two 4-inch (102 mm) deck guns.[2]

HMS L56 was laid down on 16 October 1917 by Fairfield Shipbuilding and Engineering Company at their Govan shipyard, launched on 29 May 1919, and completed on 3 September 1919. The boat was sold for scrap on 25 March 1938.

• Akermann, Paul (2002). Encyclopaedia of British Submarines 1901–1955 (reprint of the 1989 ed.). Penzance, Cornwall: Periscope Publishing. ISBN 1-904381-05-7.
• 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.
• Gardiner, Robert & Gray, Randal, eds. (1985). Conway's All the World's Fighting Ships 1906–1921. Annapolis, Maryland: Naval Institute Press. ISBN 0-85177-245-5.
• Harrison, A. N. (January 1979). "The Development of HM Submarines From Holland No. 1 (1901) to Porpoise (1930) (BR3043)". RN Subs. Retrieved 27 September 2022.