WHY hasn鈥檛 anyone made amphibious cars that can zip along at a decent clip? Until now they have been heavy, underpowered, snub-nosed beasts, incapable of going faster than 10 kilometres per hour.
But after a seven-year development programme 鈥� in which it filed some 60 patents 鈥� a UK-based engineering company believes it has cracked the problem. The result, the Aquada sports car, is being launched this week: it can reach 160 kilometres per hour on the road and up to 50 km/h on the water 鈥� as first predicted on Newscientist.com in July 2001.
With an estimated price tag of around 拢50,000, Gibbs Technologies of Nuneaton, Warwickshire, hopes its amphibian will appeal to the more deep-pocketed lovers of water sports 鈥� especially in places like the Florida Keys, the Great Lakes of North America and the inshore waters of the Greek islands. It hopes major car makers will license the technology and make it more affordable.
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鈥淧revious amphibians have been either a car or a boat first of all,鈥� says Neil Jenkins, the firm鈥檚 managing director. 鈥淭he Aquada is a unique vehicle designed from scratch to be amphibious. It鈥檚 not a boat with wheels or a waterproof car.鈥�
The main problem for previous amphibious car designs has been that they pushed their way through the water and created a bow wave, with the engine powering conventional screws. From the Schwimmwagen 鈥� an amphibious 1942 variant of the Volkswagen Beetle 鈥� to the 1960s Amphicar, such designs have never exceeded 10 kilometres per hour. 鈥淎 decent swimmer could outpace them,鈥� says Jenkins.
His answer is a three-seater vehicle made of lightweight carbon composite with enough propulsive power to lift most of its bulk out of the water, allowing it to 鈥減lane鈥� along on top of the water rather attempting to plough through it. To do this, Gibbs developed a diminutive water jet pump engine 鈥� similar to those on jet skis 鈥� which is nevertheless capable of delivering a full tonne of thrust. The novel jet pump is half the length and one third the normal weight of those used on speedboats.
Powered by the car鈥檚 2.5-litre petrol engine, the jet pump accelerates the vehicle to more than 50 km/h, aided by a low-drag hull shaped like a shallow V. The hull is also fully roadworthy and even drives safely over speed humps, says Jenkins. With aluminium crush structures built-in, the Aquada has passed all necessary European Union crash tests.
Aquada鈥檚 computer-controlled retractable wheels are reminiscent of those on James Bond鈥檚 Lotus Esprit-based submarine in The Spy Who Loved Me. When driven down a slipway into the water, its wheels disengage from the steering and transmission shafts, and tuck under the wheel arches. Just enough tyre is left poking out to fend off a jetty.
While the speed limit on rivers in the UK is 10 km/h, there shouldn鈥檛 be a problem on wider waterways such as the Thames estuary. 鈥淲e wouldn鈥檛 necessarily have a negative view of this vehicle as long as it has a sensible way of operating,鈥� says Ray Blair, deputy harbourmaster at the Port of London Authority. He says fast craft may be acceptable if, like the Aquada, they can plane across the water, minimising wash.