HMS Vindictive, ex-Cavendish, started life as a heavy cruiser but was converted to an aircraft carrier with flight decks fore and aft along the lines of HMS Furious (see Anker An17). This was not a success and after the end of WW1, she was converted back to a cruiser. In the 1930s she was de-militarised as a training ship and after the outbreak of WW2 she was converted to a repair ship.