A depot ship is a ship which acts as a mobile or fixed base for other ships and submarines or supports a naval base. Depot ships may be specifically designed for their purpose or be converted from another purpose. They are especially used as bases for submarines, fast attack craft or small minesweepers, which have little space for the crew to relax.
In the Royal Navy, under section 67 of the Naval Discipline Act 1866, the provisions of the act only applied to officers and men of the Royal Navy borne on the books of a warship. When shore establishments began to become more common it was necessary to allocate the title of the establishment to an actual vessel which became the nominal depot ship for the men allocated to the establishment and thus ensured they were subject to the provisions of the Act.1
Stone frigate, a shore establishment listed as a ship for the purposes of naval organization.