apr 30, 1917 - German U-boats
In 1916, the German and British navies fought a major naval battle with their battleships. Each side sank many ships, but neither side won a clear victory.After that battle, Germany changed its approach to naval warfare. Its new strategy resulted from Germany's development of armed submarines, or U-boats. Moving silently under the sea, U-boats went undetected until it was too late to stop their torpedoes from reaching their targets. In the first four months of 1917, German U-boats sank more than 1,000 ships carrying supplies and weapons to Allied ports. British Admiral John Jellicoe warned, "It is impossible to go on with the war if losses like this continue."
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