Crewless ships steered by computer-controlled autopilots could become reality in the next century, with the help of a University of Plymouth project which has been investigating marine control systems.

Conventional "off the shelf" ship autopilots often cannot distinguish between the different vessels in which they may be fitted. At the moment, an identical autopilot system might be fitted to a fishing trawler and an offshore powerboat. But these vessels handle very differently and tend to be used in different conditions.

Roland Burns, of Plymouth University's school of manufacturing, materials and manufacturing engineering, explained: "The problems are: how to get an autopilot that can adapt to a range of vessels; and how to get an autopilot that can adapt to different sea states."

The Plymouth team, in collaboration with the Dorset company Cetrek, developed an autopilot which can change its own rules during a voyage. In traditional systems, the compass bearing and rudder position are compared to the desired course, and a correction then made to the rudder according to fixed rules programmed into the system.

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By using an artificial intelligence technique called "fuzzy logic", the new autopilot can change the rules, depending on the sea conditions. The new rules are then temporarily stored in the system's memory.

This sort of control system could also be used in dishwashers, gas boilers and videocameras, among other things.

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Dr Burns said: "The aim in all cases is to minimise energy consumption using fuzzy logic."

He sees the development of quick, responsive and energy efficient autopilots as part of a trend towards total ship automation. "The latest designs of ship bridges are built for just one man to keep an eye on things."

Safety could be improved by automation, he says, as humans cause 80 per cent of sea accidents.

However, a more traditional maritime danger could surface once again. "The Japanese are looking at how you could have a flotilla of 20 (unmanned) ships, with one manned mother vessel, to mend breakdowns and to guard against piracy."

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