The Deepest-Diving Submarine in History
Commissioned in 1968, USS Dolphin (AGSS-555) set records as the deepest-diving operational submarine, reaching depths of over 3,000 feet. Designed as a research and development vessel, she played a critical role in advancing undersea technology, contributing to breakthroughs in sonar systems, submarine-to-aircraft communication, and non-acoustic anti-submarine warfare. In 1969, she launched a torpedo from the deepest depth ever recorded, cementing her legacy in naval history.
Unlike traditional attack submarines, Dolphin was engineered for flexibility, with a simple yet robust hull design that allowed for easy modifications. She supported both Navy and civilian research efforts, conducting deep-sea acoustic studies, oceanic surveys, and sensor trials. Her career spanned nearly four decades, making her the longest-serving diesel-electric submarine in U.S. Navy history. Despite an emergency fire and flooding incident in 2002, her crew’s quick response saved the vessel, allowing her to return to service after extensive repairs.
Decommissioned in 2007, Dolphin was transferred to the Maritime Museum of San Diego, where she became a museum ship in 2009. Visitors can now step aboard and explore her compact yet sophisticated interior, gaining insight into her groundbreaking missions and the extreme conditions faced by her crew in the depths of the ocean.
