3.3 War on the Seas  

Submarine Warfare

Early in 1915, Germany turned to a dreadful new weapon to even the odds at sea. It mounted a counter blockade of Great Britain with two dozen submarines, or Unterseeboote, called U-boats. Germany promised not to sink any American ships, but soon a new issue grabbed the headlines: the safety of American passengers on belligerent vessels.

The Lusitania

On the morning of May 7, 1915, the British passenger liner Lusitania appeared out of a fog bank off the coast of Ireland on its way from New York to Southampton. The commander of the German U-20 could hardly believe his eyes: the giant ship filled the viewfinder of his periscope. He fired a single torpedo. A tremendous roar followed as the Lusitania’s main boilers exploded.

The ship stopped dead in the water and listed so badly that lifeboats could barely be launched before the vessel sank. Nearly 1200 men, women, and children perished, including 128 Americans.

The Sussex Pledge

A month later a U-boat commander mistook the French steamer, Sussex, for a mine layer and torpedoed the unarmed vessel as it ferried passengers and freight across the English Channel. Several Americans were injured. In mid-April, President Wilson issued an ultimatum. If Germany refused to stop sinking nonmilitary vessels, the United States would break of diplomatic relations. War would surely follow. Without enough U-boats to control the seas, Germany agreed to Wilson’s terms, all but abandoning its counter-blockade.

This Sussex pledge gave Wilson a major victory, but carried a grave risk. If German submarines resumed unrestricted attacks, the United States would have to go to war to fulfill its threat. By the end of 1915, frustration with German submarines led Wilson to join the cause. He toured the country promoting preparedness and promising a “navy second to none.” In Washington, he pressed Congress to double the army, increase the National Guard, and begin construction on the largest navy in the world. On January 31, 1917, the German ambassador in Washington announced that unrestricted submarine warfare would resume the next day. Wilson’s dream of keeping the country from war collapsed. He asked Congress for the authority to arm merchant ships and in early February severed diplomatic relations with Germany.