h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Unlimited Hydroplanes are an oxymoron as they are limited in many ways, have as little do with water as possible trying to skim just above it, but aren't going to be confused as a plane by anybody except perhaps a nearsighted Vogon. Why they're don't include "boat" remains a mystery or at least a well-guarded trade secret.

Regardless of these contraditions these machines are supremely fast, noisy, interesting contraptions, and exciting to watch. Raced in primarily in the United States they regularly exceed 190 mph (300 kph) on water while kicking up a roostertail that actually makes the boat itself small in comparison.

Eclipsing this violation of visual physics also is an auditory assault that is either described by watching "boat heads" as an "twelve very angry engine pistons competing with each other" for those older boats running WWII fighter aircraft engines or "a badger with a megaphone strapped to his mouth while stepping on his testicles" for the boats running Vietnam heavy-lift helicopter turnbines.

The point of this speed is, of course, to overcome the drag effect of a 3 foot long, 6 inch thick, steel dragging in the water called a "sponson". It's a good thing they have the sponson thingy though, because after going 190 mph in a straight line the driver is suddely confronted with a rather sharp left turn to make. On the turn this sponson goes from a mere annoyance of drag to a cartoonish hook inwhich the boat pivots left violently. If one can listens carefully over the insane engine noise you can actually here water molecules being ripped apart in a giant tearing sound.

Of course the boats repeat this process 11 more times each race.

The drivers are perhaps even more interesting than the contraptions they drive. They have the same eye crazed look as the Australian guy that pokes snakes on TV. And when asked what the scariest part about driving these loud machines they confidently say, "When it gets quiet I freak out."

It seems that these quasi boats are in fact equipped with feet rudders like planes, but instead of controlling left/right yaw they control small up/down canards near the front. "You want to hear and feel a 'patang' 'patang' sound like you're inside a garbage can and somebody is dragging you around on gravel at 100 mph. When it gets quiet you push both feet to the ground and hope it gets noisy again REAL QUICK! Because if it doesn't you're going to suddenly see where you've just been and in an Unlimited Hydroplane that means you're doing a back flip and that just plane sucks."

One driver successfully "blew over" in one race, had another hydroplane land on top of him in a second race, and even won the last race, but then again he was that neighbor kid we all that you could trick into jumping off the garage with an umbrella in hand.

http://www.hydroprop.com/