DSV-4 (formerly known as ''Sea Cliff'') is a 25-ton, crewed deep-ocean research submersible owned by the

United States Navy The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...

, now known only by its

hull number Hull number is a serial identification number given to a boat or ship. For the military, a lower number implies an older vessel. For civilian use, the HIN is used to trace the boat's history. The precise usage varies by country and type. United S ...

, not by its former name. DSV-4 is an ''Alvin''-class

deep submergence vehicle A deep-submergence vehicle (DSV) is a deep-diving crewed submersible that is self-propelled. Several navies operate vehicles that can be accurately described as DSVs. DSVs are commonly divided into two types: research DSVs, which are used for ex ...

(DSV), a

sister ship A sister ship is a ship of the same class or of virtually identical design to another ship. Such vessels share a nearly identical hull and superstructure layout, similar size, and roughly comparable features and equipment. They often share a ...

to ''Turtle'' (DSV-3), ''Alvin'' (DSV-2). The ''Alvin''-class DSVs were designed to replace older DSVs, such as the less-maneuverable ''

Trieste Trieste ( , ; sl, Trst ; german: Triest ) is a city and seaport in northeastern Italy. It is the capital city, and largest city, of the autonomous region of Friuli Venezia Giulia, one of two autonomous regions which are not subdivided into provi ...

''-class

bathyscaphe A bathyscaphe ( or ) is a free-diving self-propelled deep-sea submersible, consisting of a crew cabin similar to a bathysphere, but suspended below a float rather than from a surface cable, as in the classic bathysphere design. The float is fi ...

s. ''Sea Cliff'' was built by

Electric Boat An electric boat is a powered watercraft driven by electric motors, which are powered by either on-board battery packs, solar panels or generators. While a significant majority of water vessels are powered by diesel engines, with sail pow ...

in Groton, Connecticut for the U.S. Navy and was completed in December 1968. It spent much of its service life on loan to the

Woods Hole Oceanographic Institution The Woods Hole Oceanographic Institution (WHOI, acronym pronounced ) is a private, nonprofit research and higher education facility dedicated to the study of marine science and engineering. Established in 1930 in Woods Hole, Massachusetts, it i ...

. DSV-4 originally had a maximum dive depth of , as all ''Alvin''-class DSVs did at first. It was redesigned to dive to and refitted in 1984. With the refit of DSV-4, the bathyscaphe DSV-1 (formerly known as ''

Trieste II Trieste ( , ; sl, Trst ; german: Triest ) is a city and seaport in northeastern Italy. It is the capital city, and largest city, of the autonomous region of Friuli Venezia Giulia, one of two autonomous regions which are not subdivided into provi ...

'') 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. The crew of the dive consisted of pilot Lt. Alan Mason and co-pilot Chief Petty Officer David Atchinson. From late September to early October 1990, over a course of 6 days, DSV-4 recovered the cargo door of

United Airlines Flight 811 United Airlines Flight 811 was a regularly scheduled airline flight from Los Angeles to Sydney, with intermediate stops at Honolulu and Auckland. On February 24, 1989, the Boeing 747-122 serving the flight experienced a cargo-door failure in fli ...

from the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

. DSV-4 has a plug hatch in diameter, held in place mechanically with hatch dogs and, while submerged, by the pressure of the water above it. DSV-4 can dive deeper than the famed ''Alvin''; however, the Super ''Alvin''-class replacement for DSV-2 is designed to dive to . ''Sea Cliff'' was retired from active service in 1998 and subsequently given to

(WHOI). The

Naval Vessel Register The ''Naval Vessel Register'' (NVR) is the official inventory of ships and service craft in custody of or titled by the United States Navy. It contains information on ships and service craft that make up the official inventory of the Navy from t ...

shows DSV-4 was returned to active U.S. Navy service on 30 September 2002 in the custody of WHOI, but an article in ''

The New York Times ''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid ...

'' indicates that it was cannibalized for parts for ''Alvin''.

Awards

Meritorious Unit Citation The Meritorious Unit Citation is a collective group decoration awarded to members of Australian military units. It recognises sustained outstanding service in warlike operations. The Meritorious Unit Citation was created in 1991, along with the ...

with three stars *

Navy E Ribbon The Navy "E" Ribbon or Battle Efficiency Ribbon (informally the Battle "E" ribbon) was authorized on March 31, 1976, by Secretary of the Navy J. William Middendorf as a unit award for battle efficiency competition. The service ribbon replaced th ...

(2 awards) *

National Defense Service Medal The National Defense Service Medal (NDSM) is a service award of the United States Armed Forces established by President Dwight D. Eisenhower in 1953. It is awarded to every member of the US Armed Forces who has served during any one of four sp ...

with two stars *

Global War on Terrorism Service Medal The Global War on Terrorism Service Medal (GWOT-SM) is a military award of the United States Armed Forces which was created through Executive Order 13289 on 12 March 2003, by President George W. Bush. The medal recognizes those military service ...

References

* *

External links

Deep Submergence Vehicles
article at the

Federation of American Scientists The Federation of American Scientists (FAS) is an American nonprofit global policy think tank with the stated intent of using science and scientific analysis to attempt to make the world more secure. FAS was founded in 1946 by scientists who wo ...

web page

Sea Cliff Seacliff or Sea Cliff or Sea Cliffe may refer to: ;Places ''Australia'' *Seacliff, South Australia, suburb of Adelaide *Seacliff Park, South Australia, a suburb of Adelaide *Sea Cliff Bridge, in Illawarra, New South Wales ''New Zealand'' *Seacli ...

Research submarines of the United States 1968 ships {{US-submarine-stub

Awards

See also

References

External links