This drawing is an accurate depiction of the submarine 'L4' (1917) in 1918 or early 1919, as built, and apparently proceeding to sea from the diesel smoke aft. She was built by Vickers at Barrow, launched on 17 November 1917 and completed on 26 February 1918. In 1919 she was modified and her disappearing gun (on the raised casing just aft of the torpedo hatch) was removed and a new gun position fitted on a raised platform in front of, and attached to, the conning tower. She is shown loading an 18-inch practice torpedo (with no warhead) and a signalman is semaphoring from the conning tower. Note that many published sources, including 'Janes Fighting Ships' and Dittmar & Colledge's 'British Warships 1914-1919', give her armament as four 21- inch torpedo tubes, but the L1- to L8-class had six 18-inch torpedo tubes (four in the bow and two abeam). The 'L4' was broken up in 1934. The pencil sketches at the bottom are of Thornycroft Coastal Motor Boats (CMBs).