DSV Alvin

''Alvin'' (DSV-2) is a crewed deep-ocean research submersible owned by the United States Navy and operated by the Woods Hole Oceanographic Institution (WHOI) in Woods Hole, Massachusetts. The vehicle was built by General Mills' Electronics Group in Minneapolis, Minnesota. Named to honor the prime mover and creative inspiration for the vehicle, Allyn Vine, ''Alvin'' was commissioned on 5 June 1964. The submersible is launched from the deep submergence support vessel , which is also owned by the U.S. Navy and operated by WHOI. The submersible has made more than 5,000 dives, carrying two scientists and a pilot, to observe the lifeforms that must cope with super-pressures and move about in total darkness, as well as exploring the wreck of ''Titanic''. Research conducted by ''Alvin'' has been featured in nearly 2,000 scientific papers.

Design

''Alvin'' was designed as a replacement for bathyscaphes and other less maneuverable oceanographic vehicles. Its more nimble design was made possible in part by the development of syntactic foam, which is buoyant and yet strong enough to serve as a structural material at great depths.

The vessel weighs 17 tons. It allows for two scientists and one pilot to dive for up to nine hours at . The submersible features two robotic arms and can be fitted with mission-specific sampling and experimental gear. The plug hatch of the vessel is in diameter and somewhat thicker than the thick titanium sphere pressure hull; it is held in place by the pressure of the water above it.

In an emergency, if ''Alvin'' were stuck underwater with occupants inside, the outer body, or cladding, of the submersible could be released and discarded using controls inside the hull. The titanium sphere would then rise to the surface uncontrolled.

Harold E. Froehlich was one of the principal designers of ''Alvin''.

History

Early career

''Alvin'', first of its ship class of deep submergence vehicle (DSV), was built to dive to . Each of the ''Alvin-class'' DSVs have different depth capabilities. However ''Alvin'' is the only one seconded to the National Oceanic and Atmospheric Administration (NOAA), with the others staying with the United States Navy.

''Alvin''s first deep sea tests took place off Andros Island, the Bahamas, where it made a successful 12-hour, uncrewed tethered test dive. On 20 July 1965 ''Alvin'' made its first crewed dive for the Navy to obtain certification. On 17 March 1966, ''Alvin'' was used to locate a submerged 1.45-megaton hydrogen bomb lost in a United States Air Force midair accident over Palomares, Spain. The bomb, found resting nearly deep, was raised intact on 7 April. On 6 July 1967, the ''Alvin'' was attacked by a swordfish during dive 202. The swordfish became trapped in the ''Alvin''s skin, and the ''Alvin'' was forced to make an emergency surface. The attack took place at below the surface. The fish was recovered at the surface and cooked for dinner. During Dive 209, on 24 September 1968 ''Alvin'' found an F6F Hellcat, #42782, 125 miles southeast of Nantucket. The aircraft had ditched 30 September 1944 during carrier qualifications; the pilot survived.

Sinking

''Alvin'', aboard the Navy tender ship ''Lulu'', was lost as it was being transported on 16 October 1968. ''Lulu'', a vessel created from a pair of decommissioned U.S. Navy pontoon boats with a support structure added on, was lowering ''Alvin'' over the side when two steel cables snapped. There were three crew members aboard ''Alvin'' at the time, and the hatch was open. Situated between the pontoons with no deck underneath, ''Alvin'' entered the water and rapidly began to sink. The three crew members managed to escape, but ''Alvin'' flooded and sank in of water in the Atlantic Ocean at approximately , about 88 nautical miles (101 miles; 163 km) south of Nantucket Island.Anonymous, ''SALVOPS 69'', Washington, D.C.:Department of the Navy Naval Ship Systes Command, 1969, pp. 1–18.

Severe weather prevented the recovery of ''Alvin'' throughout late 1968, but it was photographed at the bottom of the Atlantic Ocean in June 1969 by a sled towed by USS ''Mizar''. ''Alvin'' was found to be upright and appeared intact except for damage to the stern. It was decided to attempt recovery; although no object of ''Alvin''s size had ever been recovered from a depth of , recovery was "deemed to be within the state of the art". In August 1969, the ''Aluminaut'', a DSV built by Reynolds Metals Company, descended to ''Alvin'' but had trouble attaching the required lines, and side effects from Hurricane Camille were producing worsening weather, causing the team to return to Woods Hole to regroup. The second attempt started on 27 August, and ''Aluminaut'' was able to secure a line and safety slings on ''Alvin'', and wrapped a prefabricated nylon net around its hull, allowing it to be hauled up by ''Mizar''. ''Alvin'' was towed, submerged at , at a speed of , back to Woods Hole.

Post-sinking career

In 1973, ''Alvin''s pressure hull was replaced by a newer titanium pressure hull. The new hull extended the submersible's depth rating.

Mid-Atlantic Ridge

With a new, stronger pressure hull ''Alvin'' could now reach the floor of the rift valley of this seafloor spreading center. In the summer of 1974 American and French scientists joined in Project FAMOUS to explore the creation of new sea floor at this spreading center. The French provided submersibles ''Archimède'' and ''CYANA''. A total of forty-four dives were completed that succeeded in defining the crustal accretion zone in the floor of the rift valley.

Hydrothermal vents

Marine geologists using ''Alvin'' in the Pacific Ocean discovered deep-sea hydrothermal vents and associated biologic communities during two expeditions to ocean spreading centers. In 1977 scientists in ''Alvin'' discovered low temperature (~20 °C) vents on the Galapagos spreading center east of those same islands. During the RISE expedition in 1979 scientists using ''Alvin'' discovered high temperature vents (380 °C) popularly known as ‘black smokers’ on the crest of the East Pacific Rise at 21° N. These discoveries revealed deep-sea ecosystems that exist without sunlight and are based on chemosynthesis.

Exploration of RMS ''Titanic''

Most famously, ''Alvin'' was involved in the exploration of the wreckage of in 1986. Launched from her support ship , she carried Dr. Robert Ballard and two companions to the wreckage of the great liner. ''Titanic'' sank in 1912 after striking an iceberg while crossing the North Atlantic Ocean on her maiden voyage.

''Alvin'', accompanied by a small remotely operated vehicle (ROV) named '' Jason Jr.'', was able to conduct detailed photographic surveys and inspections of ''Titanic''s wreckage. Many of the photographs of the expedition have been published in the magazine of the National Geographic Society which was a major sponsor of the expedition.

The Woods Hole Oceanographic Institution team involved in the ''Titanic'' expedition also explored the wreck of the , a armed with nuclear torpedoes, which sank off the coast of the Azores in 1968 in uncertain circumstances. ''Alvin'' obtained photographic and other environmental monitoring data from the remains of ''Scorpion''.

Recent overhauls

Over the years, ''Alvin'' has undergone many overhauls to improve its equipment and extend its lifetime. In 2001, among other equipment, motor controllers and computer systems were added. The current ''Alvin'' is the same as the original vessel in name and general design only. All components of the vessel, including the frame and personnel sphere, have been replaced at least once: see Ship of Theseus. ''Alvin'' is completely disassembled every three to five years for a complete inspection. A new robotic arm was added in 2006.

Recent work

In June 2008 construction started on a stronger and slightly larger personnel sphere which may be used to upgrade ''Alvin'' (for use from 2011), before being used in an entirely new vehicle. The new sphere was designed, and then forged, from solid titanium ingots, in two equal halves, at Ladish Forge, Cudahy, Wisconsin, and then the 15.5 tonnes of titanium was machined and assembled, utilizing five view ports (instead of the current three) and is designed for depths of over , where ''Alvin''s constructed depth limit was . This, along with a general upgrade of support systems, instruments and materials, will allow ''Alvin'' to reach 98% of the ocean floor. After one last dive to assess damage to the Gulf of Mexico's seafloor after the ''Deepwater Horizon'' disaster, ''Alvin'' was refitted starting January 2011, with an expected return to the ocean in 2012 and full depth potential achieved in 2014.

2014 overhaul

In early 2014, an extensively refitted ''Alvin'' started verification testing in the Gulf of Mexico. Featuring new cameras, lighting, and a larger titanium personnel sphere, this new ''Alvin'' is the result of a three-and-a-half-year effort to bring the sub to new depths. In March and April 2014, ''Alvin'' was used to explore the site of the 2010 Deepwater Horizon oil spill.

Current status

As of late 2022, ''Alvin'' is in active service, operated by the Woods Hole Oceanographic Institution. The research ship RV ''Atlantis'' serves as its support ship.

Awards

*National Defense Service Medal with 2 stars (3 awards)
*Global War on Terrorism Service Medal

Operation

''Alvin'' uses four steel weights (~1.7 cubic feet of steel) to provide negative buoyancy for the trip to the ocean floor. ''Alvin'' contains a ballast and trim system, but the steel weights allow deep dives to be achieved more rapidly. These weights are jettisoned on each dive and left at the bottom.

See also

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''Alvin''-class DSV

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Other deep submergence vehicles

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Notes

References

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External links

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WHOI's Alvin pages

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United States submarine accidents
Woods Hole Oceanographic Institution
Research submarines of the United States
1964 ships