Kaiser Wilhelm the 2nd of Germany had long desired to rule an empire. He thought that Germany needed a powerful Navy to protect it - especially against Britain. The German Navy was set to the ultimate test - war against Great Britain, putting their mighty fleet to good use. They began a naval blockade of Germany during the first days of the war and deployed their naval units. At the outset of World War I, German U-boats, though numbering only 38, achieved notable successes against British warships. By the end of the war Germany had built 334 U-boats and had 226 under construction. The Armistice terms of 1918 required Germany to surrender all its U-boats, and the Treaty of Versailles forbade it to possess them in the future.