The crane business run by Ken Smith was set up by a man called, appropriately enough, Bill Hook.

Now Motherwell-based William Hook has spun out a product development and sales business which Smith believes has the potential to match the original company's turnover.

Hook Marine is on the brink of the first orders for its Kranskan crane safety device, which tells operators electronically if the crane is overloading or if the boat platform it sits on is in danger of capsizing.

Smith reckons that, even if he took 30% of the potential market for cranes on workboats, fish farms, piers, and harbours, it could be worth (pounds) 250,000 a year, closing quickly on William Hook's turnover of (pounds) 300,000 in the financial year ending this month.

The potential could be even greater if legislation is introduced to enforce the current

regulations which stipulate a ''heel angle'' - how far the boat leans over to one side - of no more than seven degrees.

Smith, a mechanical engineer to trade, acquired William Hook for an undisclosed sum in 1994, when its main business was spare parts and second-hand cranes for the construction and plant hire industries.

''It was a fairly sleepy company, and a bit run-down,'' he said at Hook Marine's office in the

Scottish Enterprise Technology Park in East Kilbride. ''We moved it forward by getting into the examination, testing, and certification of cranes.''

Although the work was mainly on land-based, wheeled and crawler cranes - ''Aberdeen has the offshore side sewn up'' - Smith's work took him increasingly into the marine market, such as workboats which service fish farms.

''It was important to diversify. Any service business is very fragile and vulnerable. If the service hours are not sold, they are simply an overhead,'' he said.

The marine work turned Smith's mind to the problems of lifting a heavy load onto a boat. ''Many of the boats I saw had lifting gear similar to the cranes you find on the backs of trucks.'' he said.

''Most of them simply had an inclinometer on the gear. But a good craneman will always be looking at the load, to make sure it's not hitting anything.

''We saw there was something missing, and developed Kranskan to provide an audible warning to the craneman if the crane is overloading or heeling dangerously.''

Smith pointed out that his device also has knock-on benefits for crane operators. ''Overloading is very damaging in the long-term and if you operate the crane at its optimum efficiency, there is obviously less wear and tear, and less maintenance,'' he said.

The development programme for Kranskan has lasted several years, with on-site testing at one of Scotland's major fish farming companies. Further development will concentrate on automatic cut-offs if specifications are exceeded, although Smith is concerned about removing the human element from complex lifting operations.

Other projects include a load indicator system for the davits

for Calmac's fast rescue boat launches, required by law after the Estonian ferry disaster. Smith is also working on a device for fishing boats at sea, which it is believed will help net recovery.

But he stressed the environmental benefits from the Kranskan idea. ''If you have a few hundred thousand salmon in cages and you capsize a boat filled with diesel beside them, it isn't going to do them much good. There are always spinoffs from safety.''