What did Germany claim about U-boats?

Germany claimed that U-boats, or submarines, were a vital part of their naval strategy during both World Wars, allowing them to disrupt enemy supply lines and assert dominance over the seas. They argued that unrestricted U-boat warfare was necessary to counteract the blockades imposed by Allied forces. This strategy, however, led to significant international controversy, particularly with the sinking of civilian ships, which ultimately contributed to shifts in public opinion and the United States' entry into World War I.