HMS Vulcan was a British torpedo boat depot ship launched on 13 June 1889, later converted to a submarine tender in 1908-09. As a training hulk, she was renamed HMS Defiance III in 1931 and used for training at Torpoint, Cornwall. She was scrapped in Belgium in 1955. The increasing numbers of torpedo boats which had entered service produced the need for a specialist support ship. Vulcan could carry six torpedo boats on her deck and had repair workshops and equipment stores. She had an armoured deck and could act as a light cruiser.