HMS Medway was the first purpose-built submarine depot ship constructed for the Royal Navy. She was built by Vickers Armstrong at Barrow-in-Furness during the late 1920s. The ship served on the China Station before the Second World War and was transferred to Egypt in early 1940. Ordered to evacuate Alexandria in the face of the German advance after the Battle of Gazala in May 1942, Medway sailed for Lebanon at the end of June, escorted by a light cruiser and seven destroyers. Her strong escort could not protect her; on 30 June a German submarine torpedoed and sank her.

HMS Titania was a Royal Navy submarine depot ship. Most of those that saw service in the First World War were scrapped in the 1930s. Titania, however, saw service in the Second World War. She was scrapped at Faslane, Scotland, in September 1949.