Unrestricted

Submarine

Warfare

By 1917, the Germans were desperate and resumed their unrestricted u boat campaign, in an effort to cripple British shipping, and force them out of the war. By this time, there were far more u boats, and there was a realistic possibility that Britain could be defeated by destroying her trade lines. However, with the Germans attacking any ship including that of neutral powers, the U.S. entered the war. This tipped the balance against Germany.