DSV-4 SEA CLIFF

• DSV-4 Sea Cliff is a deep-submergence vehicle (DSV) operated by the United States Navy, designed for undersea rescue and research missions. • Sea Cliff was launched in 1968 and became operational in 1969, making it one of the earliest deep-submergence vehicles in the U.S. fleet. • Originally, Sea Cliff could dive to a depth of 6,000 feet (1,830 meters), but after major upgrades in the early 1980s, its maximum depth was extended to 20,000 feet (6,100 meters). • The hull of Sea Cliff was upgraded from steel to titanium during its 1980s refit, making it only the second DSV in the world (after Alvin) to use titanium for such purposes. • Sea Cliff participated in several notable recovery operations, including the investigation of the wreckage of the space shuttle Challenger in 1986. • The DSV-4 was involved in undersea espionage missions during the Cold War, including cable tapping and intelligence-gathering operations. • Sea Cliff contributed to scientific exploration by studying hydrothermal vents, marine biology, and deep-sea geology, expanding knowledge of the deep ocean. • The vehicle was featured in the 1988 IMAX film “The Deepest Dive”, showcasing its advanced capabilities and the challenges of deep-sea exploration. • DSV-4 was part of the U.S. Navy’s Submarine Rescue Program, capable of assisting in submarine accidents and locating sunken vessels. • Sea Cliff was officially retired in 1998 after nearly 30 years of service, having completed hundreds of dives and significantly contributing to both military and civilian undersea operations.