An 80-year-old technology which enables vehicles to skim over water at high-speeds has found a commercial application in the form of Xtreme Xplorer, a pleasure cruiser developed in the Bahamas.
When an aircraft attempts to land, and the wing gets close to the ground, it experiences lift, which causes the aircraft to move faster and more economically. Known as ground effect, this occurs because of an increase in pressure on the underside of the wing.
Numerous attempts have been made to exploit this force and build a Wing-In-Ground effect vehicle (WIG).
Like a hovercraft, a WIG generates an air cushion on which it rides. The difference is that, while a hovercraft rides on a static air cushion (air is blown vertically under the craft), a WIG craft rides on a dynamic air cushion which is generated by its own forward motion.
At the height of the cold war, research really began in earnest. Recognising the military potential of craft which could travel quickly and efficiently over the ocean, Russian scientists began working on the development of Ekranoplans. These projects quickly led to the development of a 550ton Ekranoplan. Dubbed the `Caspian Sea Monster’ this craft achieved a stable flight speed of 500km/h at a height of 20m.
As interest cooled and the cold war thawed, scientists working on these projects began taking their ideas to the west, and a direct descendent of the Caspian Sea Monster is Amphistar’s Xtreme Xplorer – the first WIG craft officially certified for commercial applications.
Designed primarily for use on sheltered waterways, and officially classified as a boat, Xtreme Xplorer cruises quietly – inches above the surface – at 106mph and consumes less than 12.5gal/100mile. Manufactured from fibre glass composite and holding five passengers, the vehicle has two air propellers which are driven by a Mercedes Benz M119 V8 car engine. The propeller angle may be varied from 0 to 60 degrees to direct air to the underside of the wings. The short and wide design of the wingspan keeps the craft stable and makes the best use of ground-effect.
The craft operates in three distinct modes: at low speeds it floats with the aid of inflatable pontoons, which also enable it to skim along the water surface like a hovercraft. However, when the vehicle reaches cruising speed, it enters ground effect mode, travelling at an altitude that is 1/10 the distance from the leading edge to the trailing edge of the wing.
Even when floating, the maximum draft of Xtreme Xplorer is only 9in, meaning that it can operate in water too shallow for conventional boats.