Submarine Warfare (WW I)

In 1917 not only did the United States enter the war, but also the Germans failed in their attempt to drive Great Britain to surrender through the destruction by submarine of the British and Allied shipping on which it depended for food and other supplies. At the outset the German submarine campaign seemed likely to succeed. Towards the end of 1916 German submarines were destroying monthly about 300,000 tons of British and Allied shipping in the North Atlantic; in April 1917 the figure was 875,000 tons. Because the Germans had calculated that the destruction of 600,000 tons monthly for six consecutive months would be sufficient to force Great Britain to capitulate, they were doubly certain of victory after April. Great Britain, however, roused itself to unprecedented efforts to fight the submarine menace. By the adoption of a convoy system of screening fleets of merchant vessels with warships, especially destroyers and submarine chasers, and by the use of hydroplanes for spotting submarines and depth charges for destroying them, Great Britain, as the summer advanced, rendered the German submarine campaign less and less effective. By the fall, although large numbers of Allied ships were still being sunk, the Germans were sustaining heavy losses in submarines. At the same time the Allied nations, especially the United States, were rapidly building new shipping. By the outset of 1918 the Allies were turning out more new ships than the Germans were destroying, and the German effort to end the war by submarine warfare had clearly failed.