The mass scrapping of obsolete ships after World War I had caused a downturn in demand for scrap iron by the time the Navy decided to sell off "Warrior" on 2 April 1925. There was no commercial interest in scrapping the old ship, and she remained at Portsmouth for another four years. She was modified into a mooring jetty beginning on 22 October 1927. This entailed the removal of all of her equipment and masts other than her boilers and generators, and the installation of two diesel-driven emergency pumps. The space under the poop was converted into accommodation for a shipkeeper and his family. The hulk was towed to her new home, Pembroke Dock in Wales, on 13 March 1929 where she served as a floating oil jetty. For the next fifty years, the ship lay just offshore from an oil depot at Llanion Cove. The Navy covered the ship's upper deck with a thick layer of concrete during one of her maintenance dockings before World War II. In the war, she served as a base ship for coastal minesweepers and, on 27 August 1942, was renamed as "Oil Fuel Hulk C77" to release her name for use by a light aircraft carrier, , then under construction. She refuelled 5,000 ships during her service at Llanion Cove.