In the first two years of World War I, the basic pattern of prewar naval
power remained intact. A superior British fleet dominated the world's
strategic oceans without facing a serious challenge. By the winter of
1916-1917, however, Germany's use of the submarine threatened to upset
a naval balance in favor of Britain that dated from the Battle of Trafalgar in
1 805. Used principally against merchant vessels, Germany had hopes—and
the Allies had fears—that the submarine would starve the British Isles into
submission and deliver victory in the entire conflict to the Central Powers.
At what can now be seen as the critical moment of the naval war, the
Allies responded. The victory over the submarine fended off one of the few
means by which Germany could prevail in battle. It may, indeed, have been
Germany's only realistic hope of outright victory—and it faded in the wake
of the convoys that dominated Allied shipping by the close of 1917.