HMS L12 was a L-class submarine built for the Royal Navy during World War I. She was one of five boats in the class to be fitted as a minelayer. The boat survived the war and was sold for scrap in 1932.

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. 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. L12 was fitted with 16 vertical mine chutes in her saddle tanks and carried one mine per chute.

Construction and career

HMS L12 was built by Vickers, Barrow-in-Furness. She was laid down on 22 January 1917 and was commissioned on 30 June 1918. The boat collided with the submarine HMS H47 off Milford Haven, Wales on 9 July 1929. She was able to surface and returned to Milford Haven; three sailors died. HMS L12 was sold to John Cashmore Ltd on 16 February 1932 for scrapping at Newport.