L9 and its successors were enlarged to accommodate 21-inch (53.3 cm) torpedoes and more fuel. The submarine had a length of 238feet overall, a beam of 23feet and a mean draft of 13feet.[1] They displaced 914LT on the surface and 1089LT submerged. The L-class submarines had a crew of 38 officers and ratings.[2]
For surface running, the boats were powered by two 12-cylinder Vickers[3] 12000NaN0 diesel engines, each driving one propeller shaft. When submerged each propeller was driven by a 600hp electric motor.[1] They could reach 17kn on the surface and underwater. On the surface, the L class had a range of 3800nmi at .[4]
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.[5] They were also armed with a 4adj=onNaNadj=on deck gun.[2] L14 was fitted with 16 vertical mine chutes in her saddle tanks and carried one mine per chute.[1]
HMS L14 was built by Vickers, Barrow. She was laid down on 19 January 1917. The boat was sold to John Cashmore Ltd in May 1934 for scrapping at Newport. The periscope from L14 is preserved at the Royal Navy Submarine Museum at Gosport. It may be the only surviving example of a World War I periscope. It was manufactured by Grubb & Co. in 1918.