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 235feet overall, a beam of 23feet and a mean draft of 13feet.[1] They displaced 960LT on the surface and 1150LT submerged. The L-class submarines had a crew of 44 officers and ratings.[2] They had a diving depth of 150feet.[3]
For surface running, the boats were powered by two 12-cylinder Vickers[4] 12000NaN0 diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 600hp electric motor. They could reach 17kn on the surface and underwater. On the surface, the L class had a range of 4200nmi at .[1]
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.[5] They were also armed with two 4adj=onNaNadj=on deck guns.[2]
HMS L69 was laid down on 7 July 1917 by William Beardmore and Company at their Dalmuir shipyard and launched on 6 December 1918. She was then towed to HM Dockyard, Rosyth for completion on 18 April 1923. The boat was sold to Arnott Young in February 1939 for scrap.
at Dalmuir.