Few terms conjured as much fear during World Wars I and II as the “U-Boat”. Short for unterseeboot (underwater boat), the U Boat preyed upon allied navies and merchant ships with impunity, attacking without warning and disappearing into the depths. The sentry standing guard at the rail of a ship not only had to worry about what they could see, but they also had to worry about what lay beneath the waves.
The first German U-Boat first set sail in 1850 (designed by inventor Wilhem Bauer). It promptly sank. It was not until World War I that the German U Boat became an integral part of the German Navy. At the start of WWI, the German Navy had 29 U Boats in active service. They were responsible for the sinking of 5 British battle cruisers in the first ten weeks of the war. The Germans not only targeted military ships. They also targeted merchant under the existing “prize rules”. The sinking of the Lusitania and the resulting death of 1,198 people is a notable example. In both WWI and WWII U Boats proved effective at maintaining blockades, harassing shipping lines, etc. At the close of both wars all U Boats were ordered to be decommissioned. It was too dangerous to allow an enemy nation to possess a U Boat. They were simply too effective.