HMS L71

HMS L71 was a late-model L-class submarine built for the Royal Navy during the First World War. The boat was not completed before the end of the war and was sold for scrap in 1938.

Design and description
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 ft overall, a beam of 23 ft and a mean draft of 13 ft. They displaced 960 LT on the surface and 1150 LT submerged. The L-class submarines had a crew of 44 officers and ratings. They had a diving depth of 150 ft.

For surface running, the boats were powered by two 12-cylinder Vickers 1200 bhp diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 600 hp electric motor. They could reach 17 kn on the surface and 10.5 kn underwater. On the surface, the L class had a range of 4200 nmi at 10 kn.

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. They were also armed with two 4 in deck guns.

Construction and career
HMS L71 was laid down on 29 August 1917 by Scotts Shipbuilding and Engineering Company at their Greenock shipyard, launched on 17 May 1919, and completed on 23 January 1920.

On commissioning, L71 joined the 2nd Submarine Flotilla, based at Devonport. The boat was sold for scrap on 25 March 1938 at Milford Haven.