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Alvin (DSV-2) is a 16-ton, manned deep-ocean research submersible owned by the United States Navy and operated by the Woods Hole Oceanographic Institutionmarker (WHOI) in Woods Hole, Massachusettsmarker. The craft was built by General Mills' Electronics Group in the same factory used to manufacture breakfast cereal-producing machinery in Minneapolis, Minnesotamarker. 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 Atlantis, which is also owned by the U.S. Navy and operated by WHOI. The submersible has taken 12,000 people on over 4,000 dives to observe the lifeforms that must cope with super-pressures and move about in total darkness. It is said that research conducted by Alvin has been featured in nearly 2,000 scientific papers.

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 three-person vessel allows for two scientists and one pilot to dive for up to nine hours at 4500 meters (15,000 ft). The submersible features two robotic arms and can be fitted with mission-specific sampling and experimental gear. The hatch of the vessel is 0.6 meters (two feet) thick , and held in place by the pressure of the water above it (it is tapered, narrower inward).



History

Early career

Alvin, first of its class of Deep Submergence Vehicle (DSV), was built to dive to 2440 meters (8000 ft). 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. On 17 March 1966, Alvin was used to locate a submerged 1.45-megaton hydrogen bomb lost in a United States Air Force midair accidentmarker over Palomaresmarker, Spainmarker. The bomb, found resting nearly 910 meters (3000 ft) deep, was raised intact on 7 April.

Sinking

The Alvin, aboard the NOAA tender ship Lulu, was lost as it was being transported in October 1968. The Lulu, a vessel created from a pair of decommissioned US Navy pontoon with a support structure added on, carried Alvin on a steel cable. The cable snapped with three crewmembers aboard and the hatch open. Situated between the pontoons with no deck underneath, the Alvin hit the water and rapidly started to sink. The three crewmembers managed to escape, but the sub sank in 1500 meters (5000 ft) of water.

Ten months later, in September 1969, the Aluminaut, another US Navy DSV owned by Reynolds Metals Aluminum Company, secured a line on the Alvin, and it was hauled up. It was so intact that lunches left on board were soggy but edible. This incident led to a more comprehensive understanding that near-freezing temperatures and the lack of decaying oxygen at depth aided preservation. Notwithstanding the preserved food aboard, the Alvin required a major overhaul after the incident.

Post-sinking career

In 1973, Alvin's pressure hull was replaced by a newer titanium pressure hull. The new hull extended the submersible's maximum depth to about 4500 meters (15,000 ft).

Black smokers

In 1977, during an expedition led by Robert Ballard and sponsored by the National Oceanic and Atmospheric Administration (NOAA), Alvin discovered and documented the existence of black smokers around the Galapagos Islandsmarker. Existing at a depth of more than 2000 meters, black smokers emit a strong flow of black, smoky water, superheated to over 400 °C (750 °F). Alvin was able to sample the water from a black smoker. Alvin discovered that the pH was roughly 2.8.

Exploration of RMS Titanic

Most famously, Alvin was involved in the exploration of the wreckage of RMS Titanicmarker in 1986. Launched from her support ship R/V Atlantis II, she carried Dr. Robert Ballard and two companions to the wreckage of the great liner. RMS 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 the Titanic's wreckage. Many of the photographs of the expedition have been published in the magazine of the National Geographic Societymarker which was a major sponsor of the expedition.

Of note, the Woods Hole Oceanographic Institutemarker team involved in the Titanic expedition also managed to locate the wreck of the USS Scorpion , a nuclear armed Skipjack class submarine which sank off the coast of the Azores in 1968. The Alvin was able to obtain photographic and other environmental monitoring data from the remains of the Scorpion.

Recent overhauls

Over the years, the Alvin has undergone many overhauls to improve its equipment and extend its lifetime. The most recent overhaul was during 2001 in which, 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. Alvin is completely disassembled every three to five years for a complete inspection. A new robotic arm was added in 2006.

Current 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 will have five view ports (instead of the current three) and is designed for depths of over 6,000 metres (Alvin = 4,500 metres).

A possible replacement

On 6 August 2004, the National Science Foundation announced the creation of a new Human Occupied Vehicle (HOV) to replace the aging Alvin. The new vehicle is being designed to dive deeper up to 6500 meters (21,000 ft) as opposed to Alvin's 4500 meters and use new scientific equipment. The personnel sphere will be larger, and it is expected that the battery capacity will be greatly increased enabling longer bottom times. The new deep sea submarine is in the preliminary manufacturing phases and is expected to be completed as early as the end of 2011. Some components of the current Alvin are anticipated to be used in the new Alvin replacement vehicle. Due to export laws, the vehicle cannot be sold to parties outside of the United States. The fate of the Alvin when this new submersible arrives is unknown, but due to the limited market for sale and stripping of components for use on the new vehicle, it will likely be placed in a museum.

Lockheed Martin is designing the Alvin replacement vehicle as a nonclassified project and classing the vehicle to American Bureau of Shipping Rules.

Contrary to a BBC article published in October 2004 , the Alvin has not yet been retired from service.

Operation

Alvin uses four 208-pound 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



Alvin class DSV



Other deep submergence vehicles



References



Notes

  1. History of Alvin : Woods Hole Oceanographic Institution
  2. http://www.whoi.edu/page.do?pid=8422 Woods Hole
  3. http://www.nytimes.com/2008/08/26/science/26alvi.html Forging a new sphere
  4. Science salutes its ocean giant, Virginia Phillips, BBC News website, 22 October 2004.
  5. MATE - Expedition Log
  6. WHOI : Oceanus : Alvin's Pilots


External links




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