The Imperial German Navy or the Imperial Navy (Kaiserliche Marine) was the navy of the German Empire, which existed between 1871 and 1919. It grew out of the small Prussian Navy (from 1867 the North German Federal Navy), which was mainly for coast defence. Kaiser Wilhelm II greatly expanded the navy. The key leader was Admiral Alfred von Tirpitz, who greatly expanded the size and quality of the navy, while adopting the sea power theories of American strategist Alfred Thayer Mahan. The result was a naval arms race with Britain, as the German navy grew to become one of the greatest maritime forces in the world, second only to the Royal Navy.
The German surface navy proved ineffective during the First World War; its only major engagement, the Battle of Jutland, was a draw, but it kept the surface fleet largely in port for the rest of the war. The submarine fleet was greatly expanded and threatened the British supply system during the U-boat campaign. As part of the Armistice, the Imper