A7-meter-long automatic (autonomous) underwater vehicle (AUV or Autosub), which operates without a pilot or control umbilicals, recently was introduced to the industry by the UK's Natural Environ-ment Research Council. The deep-submergence vehicle was developed over 10 years by the Southampton Oceanography Centre in South-ampton, UK at a cost of £5.3 million.
"There's nothing quite like it in the world," said Gwyn Griffiths of the oceangraphic center. The intelligent underwater research vehicle weighs 1,500 kg, is designed to collect scientific data from the oceans, and has three advantages over existing remotely operated vehicles. The unit:
- Can access areas too dangerous for divers
- Is far cheaper than a manned research submarine
- Has less impact on the biological life it studies than a ship trailing a drogue (collection device).
Multiple missions
The Autosub is capable of carrying a varying scientific payload, which is changed to suit each mission. The scientific instruments for the missions are stowed in the nose cone, alongside data-loggers and control equipment.
The extremely strong central hull protects the batteries from the high pressures in deep water. At the tail end is a five-blade propeller and fins to angle the nose downwards, allowing it to dive automatically when it moves forward.
It has a radio modem (active when it is on the surface), which can download instructions from a mother ship as long as it is within a 1-km range. It can also send back any data it has already collected to allow scientists to start analysis.
An array of communication methods, including satellite, radio, and acoustic navigation links, can be used to track the unit's movement underwater. Several important industries can benefit from Autosub's work, including coastal and environmental management to monitor waste, natural hazards, environmental changes, and biodiversity.
Sensing, detection devices
The vehicle houses sensors for the exploration of oil, gas, and mineral resources and can be used for defense purposes and other types of offshore industry. (See related story, page 62.) The unit can be used to monitor and detect dissolved chemicals, including oxygen and nitrate ions, in seawater.
The unit may be used to carry out routine sampling - acting as an "underwater satellite," and according to project leader Nick Millard, could, in the future, reduce the need for large research ships. Scientific crews could instead be engaged in other areas of scientific research.
The AUV project has successfully carried out more than 200 scientific missions to date. Some of Autosub's initial trials were co-sponsored by the United States Office of Naval Research to demonstrate AUV technology operating on the edge of the Gulf Stream. According to the Autosub 1 development team, the main limit to the vehicle's capabilities is how much energy it can carry aboard to power itself.
Improved power
To reach its full potential and undertake long-distance missions, a new kind of battery is needed. "When the electric vehicle industry makes available affordable, large capacity rechargeable lithium-ion batteries, Autosub 1 will be ready to travel 1,000 km," said Griffiths.
The vehicle is undergoing trials off Plymouth, southwest England, in preparation for voyages next winter to the Antarctic where it will investigate krill populations under the ice. Krill are the basic diet of Antarctic sea birds and mammals. The Autosub will be programmed to monitor krill populations in collaboration with the British Antarctic Survey.
Editor's Note: Halliburton Subsea and Southampton University have signed an agreement giving Halliburton use of the Autosub for the oil and gas and subsea cable markets. Further information on the unit may be obtained by contacting the Southampton Oceanography Centre at e-mail: [email protected].
