The USS Plunger (SS-2) was a United States Navy submarine that served during the early 20th century. Launched in 1902, it was one of the first submarines in the U.S. fleet, designed for underwater warfare. The vessel was powered by a combination of electric batteries and a gasoline engine, allowing it to operate both submerged and on the surface. The USS Plunger was primarily used for training and experimental purposes, contributing to the development of submarine technology. It was decommissioned in 1913 and later scrapped, marking the end of its service. The submarine played a role in shaping future designs, influencing later classes like the B-class submarines.