A detailed description of the twin-screw torpedo depot ship H.M.S. Vulcan (length between perpendiculars 350 feet, beam 58 feet, draught 23 feet; displacement 6630 tons) built in Portsmouth Dockyard; the Vulcan was intended to accompany a fleet at sea as a depot for mining and countermining stores, electrical gear, Whitehead torpedoes etc., to assist in the laying and retrieval of mines, and as a school of instruction in these techniques in times of peace.