During World War II, submarines played a crucial role in naval warfare. They were used for stealthy attacks on enemy ships and to disrupt supply lines. The most notable submarines included the German U-boat, which targeted Allied merchant vessels, and the American Gato-class, known for its effectiveness in the Pacific Theater. Submarines operated under the surface, making them difficult to detect. They utilized torpedoes as their primary weapon, allowing them to sink larger ships from a distance. The advancements in submarine technology during this period significantly changed naval strategies and contributed to the overall outcome of the war.