A "U-boat" is a type of submarine used by the German Navy, particularly during World War I and World War II. The term "U-boat" comes from the German word "Unterseeboot," which means "undersea boat." These vessels were primarily designed for stealthy underwater warfare, allowing them to attack enemy ships and disrupt supply lines. U-boats played a significant role in naval battles, employing torpedoes to sink merchant and military vessels. Their effectiveness led to the implementation of convoy systems by the Allies, which aimed to protect ships from U-boat attacks. The U-boat campaign significantly impacted maritime strategy during both wars.