DSV Sea Cliff

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DSV-4 (formerly known as Sea Cliff) is a 25-ton, manned deep-ocean research submersible owned by the United States Navy, now known only by its hull number, not by its former name.

DSV-4 is an Alvin-class deep submergence vehicle (DSV), a sister ship to Turtle (DSV-3), Alvin (DSV-2). The Alvin-class DSVs were designed to replace older DSVs, such as the less-maneuverable Trieste-class bathyscaphes. DSV-4 originally had a maximum dive depth of 6,500 feet (2,000 m), as all Alvin-class DSVs did at first. It was redesigned to dive to 20,000 feet (6,100 m) and refitted in 1984. With the refit of DSV-4, the bathyscaphe DSV-1 (formerly known as Trieste II) was retired from service.

In 1985 the Sea Cliff made a record dive for this vessel type by diving 20,000 feet off Guatemala's Pacific Coast.[1] The crew of the dive consisted of pilot Lt. Alan Mason and co-pilot Chief Petty Officer David Atchinson.

DSV-4 has a plug hatch 2 feet (0.61 m) in diameter, held in place mechanically with hatch dogs and, while submerged, by the pressure of the water above it. DSV-4 can dive 5,000 feet (1,524 meters) deeper than the famed Alvin; however, the Super Alvin-class replacement for DSV-2 is designed to dive to 22,000 feet (6,705 meters).[citation needed]

Sea Cliff was retired from active service in 1998 and subsequently given to Woods Hole Oceanographic Institution (WHOI).[2] The Naval Vessel Register shows DSV-4 was returned to active U.S Navy service on 30 September 2002 in the custody of WHOI,[3] but an article in The New York Times indicates that it was cannibalized for parts for Alvin.[4]

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  1. ^ REZA, H. G. (1985-03-30). "Vessel Returns to Point Loma : Navy Vehicle Takes a Plunge to a Record Depth". Los Angeles Times. ISSN 0458-3035. Retrieved 2017-12-21.
  2. ^ "U.S. Navy Gives Woods Hole Oceanographic Institution Deep Diving Submarine". Woods Hole Oceanographic Institution. July 31, 1998.
  3. ^ "NO NAME (DSV 4)". Naval Vessel Register. US Navy. 27 June 2018. Retrieved 5 May 2019.
  4. ^ Broad, William J. (September 1, 1998). "For Aging Ocean Explorer, a New Life at New Depths". The New York Times.

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