The large German submarines were able to remain away from port for 25 days, while the smaller ones could remain away for 14 days.
In the early days of the war, the Dover Patrol consisted of old Tribal Class Destroyers with a motley group of vessels – trawlers, minesweepers – many of them paddle steamers – armed yachts, submarines, planes and airships. By the end of the war, Britain had a fleet of modern Torpedo Boat Destroyers and a mined barrage was placed across the Channel that was illuminated at night.
The work and the men of the Dover Patrol is commemorated on memorials in Britain (St. Margaret’s Bay, Dover), France (Cap Griz Nez) and America (Fort Hamilton, New York)
Source: ‘The Years of Promise’, Cecil Roberts, published by Hodder & Stoughton, London in 1968.