Sea-Doo is not new to manufacturing underwater propulsion devices. Its 'yellow' model, as it is known, has been around for more than three years now and has proved popular with snorkellers and shallow-water divers all over the world. The original model was conceived and developed by inventor Sir Clive Sinclair. When it came to mass production, a partnership with the sea craft manufacturer Bombardier was formed and the company's first sea scooters started to appear. Their main attraction was their affordability. They were a quarter of the price of other models on the market and with their compact size it made them easy to take travelling. There was, however, a major flaw in their design for the sports diver. The maximum depth rating was just 10m (later increased to 20). Furthermore, they struggled to achieve a meagre 2mph and battery life was at best 50 minutes.

All this has changed with Bombardier's introduction of the GTI version. A deep grey/blue colour replaces the yellow and it is altogether sleeker and sexier to look at. The maximum speed has been tweaked to 2.5 mph, and the battery life almost doubled to 90 minutes. But the major attraction is its depth rating of 30m, making it a suitable diving tool for the sports diver.

The DIVE test team went to the London School of Diving, based in Chiswick to find out how it performs. It takes a few minutes of getting used to, but once you have mastered the technique, it's great fun. You are effortlessly pulled along, can turn on a sixpence and can easily follow the contours of the bottom. The manual recommends that you hold the seascooter under your chest for maximum speed. We found this to be true, but after a short while it became tiring on the arms. The technique we adopted was to use it with outstretched arms when going in a straight line.

This requires little energy and doesn't tire out your biceps. When cornering, the position suggested in the manual is best, and an additional kick from your fins makes the whole manoeuvre one swift movement. After playing with the GTI for well over an hour there was still plenty of juice left in the battery. We compared notes with the school's co-owner Mark Wood. He has conducted extensive trials with the Sea-Doo and we both came to the conclusion that this is the first scooter aimed at sport diving with a reasonable price tag. The seascooter is made from ABS plastic and has waterproof circuitry for protection against accidental flooding. A further clever feature is the adjustable buoyancy nose cone. Out of the box it is slightly buoyant. This is ideal for snorkelling or for younger users, where if you let it go it will float. However, for underwater use, the addition of a 1kg weight makes it slightly heavy and easier on the wrists.

Recharging the battery takes about five hours and the whole unit weighs in at 8.4kg including the 12-volt 14Ah battery.
The only modification I would make would be to the trigger mechanism. The seascooter is activated by squeezing two levers - one on each of the handles. This is a safety feature for the younger users. However, for adults who are familiar with the unit it would be better to have the right one taped up, allowing you to be able to clear your ears while still whizzing along. Further modifications will soon be available from the manufacturer, including the addition of lights and an underwater video camera mounting plate.

Apparently there is a new sport called 'Aquajet racing', using these seascooters. This takes the form of a timed trial around a swimming pool and involves an underwater course consisting of a range of sunken hoops and slalom gates.

I can see the GTI selling well to clubs and overseas liveaboards, as well as the diving enthusiast.

Value verdict: 9 oout of 10
Performance verdict: 9 out of 10
Great fun at a good price