HMS L10

HMS L10 was a L-class submarine built for the Royal Navy during World War I. The boat was sunk in 1918 by German torpedo boats.

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.

Construction and career
HMS L10 was built at Dumbarton by William Denny. She was assigned to serve in the North Sea against German surface units counteracting German efforts to sow mines in British waters. Her greatest success led to her destruction, when on the morning of 3 October 1918, aged just under four months, the L10 surfaced in the Heligoland Bight with the mission of intercepting a German raiding party. This group, consisting of the torpedo boats SMS S34 (1914), SMS S33 (1914), SMS V28 and SMS V79, had been delayed in the Bight because the S34 had detonated a mine. The other torpedo boats were crowded round their damaged comrade, and so it was easy for L10's commander, Alfred Edward Whitehouse to sneak into position and put a torpedo into the S33, which began to sink. However, as she fired, the L10 rose suddenly to the surface and was seen instantly by the V28, S33, S 60 and V79. Although she turned and tried to flee, L10 was not fast enough to escape her pursuers and was rapidly chased down and sunk at 11:03 (CET) with all hands. S33 was scuttling by a torpedo from S52. L10 was the only L-class boat to be lost during the First World War.

Discovery
On 5 March 2020, it was announced that the wreck of L10 had been found near the island of Terschelling. The discovery was made by the Danish company JD-Contractor, who were searching for the Polish Submarine ORP Orzeł (1938).