WORLD WAR I, NAVY IN

The United States entered World War I on the side of the Allies in response to Germany's use of submarines against U.S. merchant ships. Under the assumption that the United States had insufficient antisubmarine warfare (ASW) capability to affect such a campaign, Germany had waged unrestricted submarine warfare. As its first task, the United States responded by temporarily setting aside a 1916 building program that was to give the nation the world's best navy in ten years and concentrating instead on building destroyers. The Navy dispatched Admiral William S. Sims, commander of the U.S. naval forces in Europe, to England on 9 April 1917. By July the Navy had dispatched thirty-five destroyers, and it sent additional ASW forces into the war zone as soon as bases to support them were provided. These ships were desperately needed: four-fifths of Britain's food, half its iron ore, and all other raw materials had to be imported. Allied shipping losses to German submarines were drastically high, exceeding 881,000 tons or more than 150 ships in April 1917 alone. To reduce these losses, the British began organizing merchant ships into convoys instead of patrolling fixed sea areas so that submarines had to avoid the convoy's ASW escort to make an attack.

The second critical task of the U.S. Navy was to transport the American Expeditionary Forces (AEF) to France before German armies on the eastern front, freed by the collapse of the Russian army after the 1917 revolution, could be employed on the western front. The initial American troop convoy, with the U.S. First Division, arrived at Saint Nazaire, France, on 24 June 1917. Over 300,000 American troops were in France when the Germans made their unsuccessful lunge at the Allied lines in the spring of 1918.

American flag shipping available for transport service included four hundred ships operating primarily in the coastal trade and another four hundred in production, but these could not carry the entire AEF. The Navy turned to the 104 German ships interned in U.S. ports, using the then-new technique of welding to quickly repair twenty ships damaged by their German crews. Mostly passenger ships, including the world's largest, Vaterland (renamed Leviathan ), they formed a considerable segment of the Naval Transport Force commanded by Admiral Albert Gleaves. This force carried 911,047 soldiers to France, about half of them in former German ships. Another million U.S. troops were transported in British vessels.

The third major undertaking of the U.S. Navy in World War I was the North Sea mine barrage: the laying of 56,600 anchored mines between the Orkney Islands and the coast of Norway. This barrage was not completed by the war's end and had no impact on its outcome.

Other U.S. naval activities in World War I included using aviation, chiefly along the west coast of France; launching submarine chaser operations in the Mediterranean and Adriatic seas; providing a division of battle-ships with the British Grand Fleet and another at Bantry Bay, Ireland, to cover the English Channel ports; stationing a naval railroad battery of fourteen-inch guns on the western front; and operating in Russian waters, both in the White Sea and the Far East.