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 naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 millio ...

, now known only by its

hull number A 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 Hull Identification Number (HIN) is used to trace the boat's history. The precise usage varie ...

, 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 Ship class, 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 o ...

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

Trieste Trieste ( , ; ) is a city and seaport in northeastern Italy. It is the capital and largest city of the Regions of Italy#Autonomous regions with special statute, autonomous region of Friuli-Venezia Giulia, as well as of the Province of Trieste, ...

''-class

bathyscaphe A bathyscaphe () 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 floa ...

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 power ...

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 initially had a maximum dive depth of ; all ''Alvin''-class personnel pressure hulls were originally designed for , but subsequent testing allowed a higher rating. In 1981, the submersible was refitted with a titanium personnel hull to dive to . With the refit of DSV-4, the bathyscaphe DSV-1 (formerly known as ''

Trieste II ''Trieste II'' (DSV-1) was the United States Navy's first bathyscaphe purchased from its Swiss designers, and the successor to ''Trieste''. History The original ''Trieste'' design was heavily modified by the Naval Electronics Laboratory in San ...

'') 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 NAVSEA system certification representative/command pilot, LCDR Rick Williams, mission 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 international 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 ...

from the

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

. 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. ''Sea Cliff'' was retired from active service in 1998 and subsequently given to

(WHOI). As of 2019, 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 September 30, 2002, in the custody of Woods Hole. Although an article in ''

The New York Times ''The New York Times'' (''NYT'') is an American daily newspaper based in New York City. ''The New York Times'' covers domestic, national, and international news, and publishes opinion pieces, investigative reports, and reviews. As one of ...

'' from 1998 indicated that DSV-4 would be cannibalized to upgrade ''Alvin'', this appears to not have taken place since: 1) the US Navy Vessel Registry shows DSV-4 as an active vessel; 2) a photo from 2005 shows DSV-4 to still be intact with its personnel pressure sphere; and 3) WHOI in its official history of Alvin does not discuss using DSV-4 parts during this timeframe. As of September 2023, WHOI does not list DSV-4 as one of their underwater vehicles.

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 A navy, naval force, military maritime fleet, war navy, or maritime force is the military branch, branch of a nation's armed forces principally designated for naval warfare, naval and amphibious warfare; namely, lake-borne, riverine, littoral z ...

(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 was awarded to every member of the U.S. Armed Forces who served during any one of four s ...

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 1945 by a group of scient ...

web page {{DEFAULTSORT:Sea Cliff

Sea Cliff A cliffed coast, also called an abrasion coast, is a form of coast where the action of marine waves has formed steep cliffs that may or may not be precipitous. It contrasts with a flat or alluvial coast. Formation In coastal areas in whic ...

Research submarines of the United States 1968 ships

Awards

See also

References

External links