DSV Alvin
Alvin is a crewed deep-ocean research submersible owned by the United States Navy and operated by the Woods Hole Oceanographic Institution of Woods Hole, Massachusetts. The original 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 June 5, 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 5,200 dives, carrying two scientists and a pilot, observing 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 previous versions of Alvin were stuck underwater with occupants inside, an upper part of the submersible including the titanium sphere could be released using controls inside the hull. This would then rise to the surface uncontrolled. The current version of the vehicle uses releasable weights and emergency releases on jettisonable equipment.
Harold E. Froehlich was one of the principal designers of Alvin.
History
Early career
Alvin, first of its ship class of deep submergence vehicle, 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, with the others staying with the United States Navy.Alvins first deep sea tests took place off Andros Island, the Bahamas, where it made a successful 12-hour, uncrewed tethered test dive. On July 20, 1965 Alvin made its first crewed dive for the Navy to obtain certification. On March 17, 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 on a steep slope nearly deep, was located by Alvin but the submersible had difficulty raising it up, initially causing it to fall deeper to. The bomb was eventually raised intact on April 7 by a Navy CURV-I and the experience gained by the Alvin crew's 34 dives with over 220 hours logged led to new improvements to the vehicle's navigations systems.
On July 6, 1967, the Alvin was attacked by a swordfish during dive 202. The swordfish became trapped in the Alvins skin. The attack took place at below the surface. The fish was recovered at the surface and cooked for dinner. During Dive 209, on September 24, 1968 Alvin found an F6F Hellcat, #42782, 125 miles southeast of Nantucket. The aircraft had ditched September 30, 1944 during carrier qualifications, with the pilot surviving.
Sinking
Alvin, aboard the Navy tender ship Lulu, was lost as it was being transported on October 26, 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 south of Nantucket Island.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 Alvins 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 August 27, and Aluminaut was able to secure a line and safety slings to Alvin and wrap a 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 refit
In 1973, Alvins 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 vents on the Galapagos spreading center east of those same islands. During the RISE expedition in 1979 scientists using Alvin discovered high temperature vents 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''
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 White Star Liner Titanic, which 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 named Jason Jr., was able to conduct detailed photographic surveys and inspections of Titanics 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.