High Quality Content by WIKIPEDIA articles! HMS Medway was the first purpose-built submarine depot ship constructed for the Royal Navy by Vickers Armstrong at Barrow-in-Furness. The Medway was launched on 19 July 1928. She was designed to support up to 18 O, P and R type submarines. She carried three 4 inch guns as spares together with 144 21 inch torpedoes to reload submarines, and 1880 tons of fuel.