HMS L4

HMS L4 was a L-class submarine built for the Royal Navy during World War I. The boat survived the war and was sold for scrap in 1934.

Design and description
The L-class boats were enlarged and improved versions of the preceding E class. The submarine had a length of 231 ft overall, a beam of 23 ft and a mean draft of 13 ft. They displaced 891 LT on the surface and 1074 LT submerged. The L-class submarines had a crew of 35 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 3200 nmi at 10 kn.

The boats were armed with a total of six 18-inch (45 cm) torpedo tubes. Four of these were in the bow and the remaining pair in broadside mounts. They carried 10 reload torpedoes, all for the bow tubes. They were also armed with a 4 in deck gun.

Construction and career
HMS L4 was built by Vickers, Barrow. She was laid down on 21 June 1916 and was commissioned on 26 December 1918. She sailed with the Submarine Depot Ship HMS Ambrose (1903) to Hong Kong in 1919 as part of the 4th Submarine Flotilla, arriving there in January 1920. On 20 October 1927 off Hong Kong, L4 and HMS L5 rescued crew of the merchant ship SS Irene from a pirate attack after firing her deck gun. HMS L4 was sold on 24 February 1934 and then broken up in Charlestown, Fife.