 During the First World War, while serving in the Royal Naval Volunteer Reserve, he was assigned to submarine patrols in the Dardanelles, Gallipoli and Gibraltar, and, beginning in 1917, to a minesweeping operation at HMNB Devonport.In April 1917, German submarines (called U-boats) achieved unprecedented success in torpedo attacks on British ships, sinking nearly eight per day.In his autobiography, Wilkinson remembers the moment when, in a flash of insight, he arrived at what he thought would be a way to respond to the submarine threat.