U-boats, short for "Unterseeboot," are German submarines primarily used during both World Wars. They were designed for stealthy underwater operations, allowing them to attack enemy ships and disrupt supply lines. U-boats played a significant role in naval warfare, particularly in the Battle of the Atlantic. These submarines were equipped with torpedoes and deck guns, enabling them to engage in both surface and submerged combat. The effectiveness of U-boats led to the development of countermeasures by the Allies, including the use of convoys and improved anti-submarine warfare tactics.