 During the First World War, three junior officers of the Harwich Force suggested that small motor boats carrying a torpedo might be capable of travelling over the protective minefields and attacking ships of the Imperial German Navy at anchor in their bases.In 1915, the Admiralty produced a Staff Requirement requesting designs for a Coastal Motor Boat for service in the North Sea.These boats were expected to have a high speed, making use of the lightweight and powerful petrol engines then available.