In the North Sea on September 22, 1914, the German submarine U-9 sinks three British cruisers, the Aboukir, the Hogue and the Cressy, in just over one hour.
The aggressive buildup of the German navy in the years before World War I, masterminded by Naval Minister Alfred von Tirpitz, had undoubtedly contributed to Britain’s anxiety and eventual animosity towards Germany. In the first two months of war, however, the German High Seas Fleet made little effort to move from its headquarters in Wilhelmshaven. The one naval battle, fought at Heligoland Bight in late August, ended in a convincing British victory, with three German battleships sunk, three more damaged and 1,200 German sailors killed or wounded.
In the wake of Heligoland Bight, Kaiser Wilhelm and the German leadership concluded that the navy should be kept off the open seas, as its best use was as a defensive weapon. As the war continued, Germany’s greatest weapon at sea would not be its light cruisers but its lethal U-boat submarine, which was far more sophisticated than those built by other nations at that time. The typical U-boat was 214 feet long, carried 35 men and 12 torpedoes and could travel underwater for two hours at a time.
The one-sided battle on September 22, which claimed three British cruisers and the lives of 1,400 sailors, alerted the British to the deadly effectiveness of the submarine, which had been generally unrecognized up to that time. In the first few years of World War I, German U-boats took a terrible toll on Allied shipping. By 1917, however, the continued unrestricted U-boat attacks on American vessels traveling to Britain prompted the previously neutral United States to declare war on Germany. The infusion of American ships, troops and arms into World War I, as well as the economic support the U.S. supplied to the Allied powers, would eventually turn the tide of the war against Germany.