Alvin

Alvin about to be lowered into the water. Once released by the A-frame, the swimmer (standing) will detach a line from the top of the sub to free it from the ship.

Alvin, which is operated by Woods Hole Oceanographic Institution (WHOI), has been in operation since 1964. It was affectionately named after WHOI engineer Allyn Vine, whose influence was pivotal in Alvin’s conception. A legendary figure at WHOI, Vine first envisioned a deep-sea research vessel in the 1930s when he was a graduate student in physics.

Alvin was the first deep-sea submersible capable of carrying passengers, usually a pilot and two observers. Its first untethered dive measured 35 ft. Now, after numerous upgrades and reconstructions, Alvin can plunge to a maximum depth of 14,764 ft.

Just as the space shuttle is built to withstand the near total vacuum of outer space, Alvin is built to withstand the crushing pressure of the deep ocean. The titanium-hulled sub can remain submerged for 10 hours under normal conditions, although its life support system will allow the sub and its occupants to remain underwater for 72 hours. It is capable of maneuvering around rugged bottom areas and can hover in midwater to perform scientific tasks or take still and video photography.

Alvin weighs 35,200 lbs. and measures 23 ft 4 in long, 12 ft high and 8 ft 6 in wide. It has a 6-mi range, a cruising speed of 1 knot and a maximum speed of 2 knots. It is propelled by five hydraulic thrusters and features an electrical system powered by lead-acid batteries.

Throughout its long career, Alvin has made over 4,600 dives, taking more than 13,000 scientists, engineers, and observers to the seafloor. Though nearly half a century old, the venerable Alvin remains a state-of-the-art vehicle thanks to continued retrofitting and maintenance performed at Woods Hole’s National Deep Submergence Facility.

During 2011-12, Alvin underwent the first stage of an extensive overhaul that expanded and increased comfort of the personnel sphere, added new viewports, and improved lighting and imaging systems. The second stage of upgrade is planned to increase Alvin’s maximum operating depth from 14,800 ft to 21,325 ft. These modifications, coupled with longer dive times made possible by continued battery upgrades, will provide a platform for investigating our deep oceans that Alvin’s original designers could have only imagined.

The end of a cruise with the deep-sea submersible (DSV) Alvin can be almost as busy as the middle. This photo, taken on April 13, 2010 after dive #4618, shows the crew of the R/V Atlantis washing the sub and preparing it for the next cruise.

The end of a cruise with the deep-sea submersible (DSV) Alvin can be almost as busy as the middle. This photo, taken on April 13, 2010 after dive #4618, shows the crew of the R/V Atlantis washing the sub and preparing it for the next cruise. Click image for larger view.

Alvin's Influential History

Alvin allows researchers to conduct biological, chemical, geochemical, geological and geophysical studies. In 1974, Alvin played a pivotal role in Project FAMOUS (French-American Mid-Ocean Undersea Study). Along with the French submersibles Cyana and Archimade, Alvin helped the French and American scientists confirm the theory of sea-floor spreading along the mid-Atlantic Ridge.

Following Project FAMOUS, Alvin’s reputation as a valued workhorse grew steadily among the oceanographic research community. In 1977, researchers using Alvin discovered the first hydrothermal vents in the Pacific Ocean off the coast of the Galapagos Islands. Since then, it has located more than 24 hydrothermal sites in the Atlantic and Pacific Oceans. It also has allowed researchers to find and record about 300 new species of animals, including bacteria, foot-long clams and mussels, tiny shrimp, arthropods, and red-tipped tube worms that can grow up to 10 ft long in some vents.

Alvin has been instrumental in locating human artifacts as well. In 1966, the sub was used to help locate and retrieve a hydrogen bomb that had been lost after an American B-52 and a tanker collided over the Mediterranean Sea. In July of 1986, Alvin made 12 dives to the RMS Titanic to test a prototype robotic vehicle called Jason Jr. and to photographically document the wreck.

Alvin’s history has not been without mishaps, however. In 1968, during preparations for a dive off Cape Cod, Alvin broke from the steel cables used to raise and lower the vessel into the water and sank more than 5,000 ft to the seafloor. Though its pilot, Ed Bland, sustained minor injuries as he exited the sub, fortunately the sub sank unoccupied. It remained on the sea floor for 11 months before it could be recovered. Though a section of the sub was damaged during recovery, Alvin was so well preserved by the near-freezing temperatures and lack of oxygen at depth that lunches that had been left on board were soggy but still edible.

Deployment and Features

Alvin makes between 150 and 200 dives every year. A typical dive measures about 6560 ft and lasts about six hours, depending on the power usage. As a general rule, the sub takes about two hours to reach the typical depth, and another two hours to surface, leaving two hours for study on the seafloor. Dive duration may be affected by weather conditions or any required launch or recovery operations. The pilot and surface controller may shorten the duration of a dive if weather conditions deteriorate.

Alvin is deployed using a large A-frame crane on the stern of the R/V Atlantis, its permanent "tender ship." With the help of nine to ten crew members, all of whom have unique roles in maintaining and preparing the sub for a dive, the crane lifts Alvin off the deck and gently sets it down in the water. After the dive, the crane lifts Alvin aboard.

Alvin is equipped with three thick portholes strategically placed for portside, starboard and forward observation. Film and video cameras are mounted on the outside of the sub. Two hydraulic manipulator arms that can lift up to 200 lbs each and reach up to 75 in are mounted on the forward end of the sub. One arm is more dexterous than the other and can perform more delicate tasks. The other arm can perform tasks that require brute force or heavy lifting. Each arm has a 6-degree range of motion.

The manipulators, along with sediment corers and water samplers, collect live biological and geological samples and store them in a basket attached to the front of the sub. Wand-shaped electrode sensors sheathed in protective coatings also can be used to take chemical readings of the environment in “real time.” Before these sensors were developed, researchers had to take water samples back to the surface for laboratory analysis.

Incandescent, sodium-scandium and thallium iodide external viewing lights allow observers to see into the pitch-black ocean environment. In addition, the sub includes a computer/data display/recording system, an altimeter, a gyrocompass, a navigation and tracking system, sonar, an underwater telephone to call the ship, temperature probes, heat flow probes, a CTD and a magnetometer. Alvin also can be fitted with a variety of other specialized equipment, depending on the needs of the scientists. The equipment, however, must be tested and certified to withstand the sea pressure before it is fitted onto the sub.

With all of these features, Alvin is not cheap. Science teams should expect to pay about $30,000 each day the Atlantis and Alvin are at sea.

 

To learn more:

Woods Hole Oceanographic Institution External Link