ABSTRACT
The decision to adopt convoy as an anti-submarine method was clearly the key event in the war at sea between 1914 and 1918. A failure to contain the U-boat menace, especially after the adoption of unrestricted submarine warfare in February 1917, would have meant severe food shortages at home, the paralysis of trade and its war-feeding profits, the absence of shells and supplies at the front, and the potential for defeat. The heavy shipping losses of the early months of 1917 provided the necessary incentive to attempt convoy as an alternative anti-submarine method. Although the decision to adopt convoy for overseas trade in late April 1917 has met with much historiographical controversy over the course of the last nine decades,1 convoy tactics nevertheless contributed decisively to a strategic defeat of the unrestricted submarine warfare campaign and ensured that Britain and her Allies would continue to fight and win the war. At its peak in April 1917, the German offensive cost the Allies 226 ships of over 500 tons GRT in all theatres; in September 1917, the worldwide losses amounted to only 87 ships.2 As the meticulous Barley and Waters staff study states, during the unrestricted submarine campaign only 257 out of 83,958 ships (over 500 tons GRT) sailed under convoy escort were lost to U-boats in Home Waters. Out of 1,757 total losses during the period, the vast majority (1,500 or 86 per cent) occurred when ships sailed independently.3 Convoys completed the Admiralty’s array of anti-submarine methods and tactics – which also included surface, submarine, and air patrols, mine barrages, and assaults on U-boat bases – but the convoy system was the most important contributor to thwarting the U-boats.
