UCI editor John Bevan recently received the red-carpet treatment at the Southampton Oceanography Centre (SOC). He was given a privileged guided tour of the "Autosub 2" AUV project, courtesy of Gwyn Griffiths, Head of the Ocean Technology Division.
This is his report.

Why AUVs? This was my first question. Surely, I thought, conventional survey techniques could provide all the necessary vehicles for oceanographic and related work, and perhaps at the same time be more cost-effective. It was also a rather clumsy attempt to get a reaction.
Gwyn Griffiths was very patient - sympathetically and systematically leading me through the technology trail that had made SOC's Autosub so famous.
First, he told me, an AUV is an extremely quiet vehicle. This makes it ideal for studies of animal populations such as fish stocks. Autosub has carried out very successful investigations into fish-stock levels in mid-water by flying below the shoals and directing sonar upwards to track and count the fish.
Second, AUVs have minimal inherent vibration. Autosub has therefore been used to obtain unique data on upper ocean physics, including the interaction of wind and water turbulence.

Under ice
Third, AUVs can operate under ice without causing any disturbance such as that a surface ship might cause as it broke through the ice. Autosub has been able to carry out research on the ecosystem of zooplankton under the ice of the Arctic. Investigations are already planned to work under 1500 metres thickness of ice.
Fourth, AUVs have a special ability for terrain-following. Autosub can therefore carry out missions where it needs to remain at a constant level above the seabed or at a constant distance below a varying depth of ice.
Fifth, AUVs can turn corners faster that ships with towed vehicles. This has great advantages in cost-effectiveness of survey operations. Autosub has carried out pollution surveys in a sea loch, exploiting this ability.

Greater speeds
Sixth, AUVs can operate at greater speeds through the water than conventional systems.
Seventh, AUVs can have excellent navigation accuracies using a combination of inertial guidance and satellite position fixing systems. Typical figures are 1% of track, or 1 metre per kilometre of track.
Eighth, AUVs can be "event-triggered". They can be garaged in a docking station where they await some predetermined event; then activate to carry out their designated functions.
Ninth, AUVs have extremely 'interesting' features useful in military applications such as mine countermeasures. But that was not in our current remit.
So, what immediately impressed me was the sheer variety of tasks that AUVs could perform, and the operational advantages that AUVs offered. It was also obvious that we were just scratching the surface of what AUVs are ultimately going to be able to do.
Autosub, like many of its contemporaries around the world, normally carries out missions lasting 24-48 hours. The main limitation is the amount of power it is able to carry with it. In Autosub's case, this is a question of how many U2 batteries it can carry. Much longer mission endurances will be possible in the future, with improved power capacities. I was a little surprised to learn that the payload of Autosub was as low as 100 kg, or 1000 litres volume.

Instrumentation
With the appearance of AUV technology, a host of new instrumentation is now being developed to take advantage of the new facility - self-contained mass spectrometers, flow cytometers, chemical sniffers, and ultra-violet fluorescence detectors, to mention but a few.
So far, AUVs have begun to flourish in the oceanographic and military domains, but the future will see an increasing application of their services in the oil and gas industry, primarily in survey work. They can search for hydrocarbons, as well as carry out site surveys and pipeline surveys. Kongsberg, Racal and Fugro are all committed to expansion in this area. And de Beers of South Africa plan to use an AUV to search for "offshore minerals". That's diamonds, to you and me.
Perhaps the most controversial aspect of AUV operations is their legal status, or more to the point, their lack of it. Is an AUV a ship, or a buoy? Neither, is the obvious reply, but for some reason, that does not satisfy the bureaucrats.
What international rules should govern their operations? Confusion reigns at the international level, with nobody yet prepared to bite the bullet. We may need to await the first serious international AUV incident before the legislators are motivated into action.
A brave attempt to rationalise the situation has been made by Prof E D Brown (Cardiff University) and Prof N J J Gaskell (University of Southampton). They have produced a ground-breaking document entitled Report on the Law Relating to Autonomous Underwater Vehicles.
This report was commissioned by Gwyn Griffiths of SOC (with support from NERC's Autosub programme), and published by the Society for Underwater Technology (SUT). To quote Mr Griffiths: "My purpose was to provide an up-to-date review on the law relating to autonomous underwater vehicles. It will prove invaluable in identifying the issues and help users to raise well-posed questions if they do need specific advice."

Two volumes
SUT are about to publish two volumes on The Operations of Autonomous Underwater Vehicles - Volume One: Recommended Code of Practice, and Volume Two: Report on the Law.
The debate as to which international organisation will provide the legal regime for future AUV operations is set to be an interesting one, with the International Oceanographic Commission in the French corner and the International Maritime Organisation in the UK corner. Seconds out!

© 2000 Underwater World Publications Ltd.