HMS L20

HMS L20 was a L-class submarine built for the Royal Navy during World War I. The boat was not completed before the end of the war and was sold for scrap in 1935.

Design and description
L9 and its successors were enlarged to accommodate 21-inch (53.3 cm) torpedoes and more fuel. The submarine had a length of 238 ft overall, a beam of 23 ft and a mean draft of 13 ft. They displaced 914 LT on the surface and 1089 LT submerged. The L-class submarines had a crew of 38 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 3800 nmi at 10 kn.

The boats were armed with four 21-inch torpedo tubes in the bow and two 18-inch (45 cm) in broadside mounts. They carried four reload torpedoes for the 21-inch tubes for a grand total of ten torpedoes of all sizes. They were also armed with a 4 in deck gun.

Construction and career
HMS L20 was laid down on 26 July 1917 by Vickers at their Barrow-in-Furness shipyard, launched on 23 September 1918, and completed on 28 January 1919. L20 was assigned to the 4th Submarine Flotilla and HMS Titania in 1919 and sailed to Hong Kong, arriving on 14 April 1920. She was transferred to the reserve flotilla in 1923 in Hong Kong. She was sold to John Cashmore Ltd on 7 January 1935 for breaking up at Newport. Her bell is in the Royal Navy Submarine Museum.