The true story behind the cataclysmic World War II naval battle that took place just off American shores. 1941. America had just entered World War II, but terrifying unseen weapons were stalking US targets, sinking over 400 ships just miles from American shores in the worst naval defeat in United States history. The stealthy predators were German U-boats, Hitler’s deadly warships of the deep. It was cataclysmic—with bodies and wreckage washed ashore on the eastern seaboard. But the Allies ultimately triumphed, sinking over 700 enemy submarines.