July 24, 2002

10:39 AM

WIG (Wing In Ground) boats are something like a cross between a hovercraft and an airplane. Taking advantage of a phenomenon that creates a cushion of air between a wing and the ground, they fly a few feet above the surface of the water, able to reach higher speeds with greater efficiency than traditional boats. The best known WIG boats are the Russian ekranoplans, and the largest and most famous of these was the KM, better known in the west as the "Caspian Sea Monster".
posted by Aaaugh! (4 comments total)

Here's another nice overview. Despite all that (mostly Russian) research, nothing much has ever come of the technology. Right now the only commercially available WIG vehicle is the Amphistar, at least one of which is now in operation in the Bahamas. I found an army college paper on ground-effect for military mobility; one obvious advantage is that a WIGE could bypass a minefield by flying over it. In any event it's something that might prove especially useful in amphibious operations where speed and surprise are essential.

They have some major disadvantages or limitations, the chief being a requirement of a relatively smooth water surface; the second is that there's a drag spike during the take-off phase that requires a lot of extra engine power or just extra engines, which increases weight and decreases efficiency. By the same token, the similar hovercraft technology had a period of popularity but is being replaced by other technology -- in the case of the well-known Channel car ferries, by hydrofoil-inspired catamaran setups, which are slightly slower but cheaper to operate and maintain -- the SeaCat and the (monohull, but using the same water-jet propulsion) SuperSeaCat seem to have captured much of the market over the last several years, such as in the Irish and Baltic Seas.
posted by dhartung at 12:32 PM on July 24, 2002

I can't find any decent links to the board but I saw surfing legend Laird Hamilton using this WIG stuff to create a surfboard (he calls it an airboard) that 'floats' 2 feet above the wave - looks stunning.
posted by niceness at 2:29 PM on July 24, 2002

Thanks Aaaugh!, this is cool. I have never heard of WIG boats before.
posted by piskycritter at 2:35 PM on July 24, 2002

As dhartung mentioned, the main problem is the requirement for a smooth water (or ground) surface, which is the same as one of the major limitations of both hovercraft and hydrofoils.

Surface-piercing craft seem to be the way of the future, providing the benefits of low drag (once on plane), stability and smooth ride. They still have the problem of needing extra power to get moving, though.

The ground-effect craft certainly have that "future-ish" aspect all sewn up though, don't they?
posted by dg at 4:04 PM on July 24, 2002