Jet boats are the big thing where I live, we run on rivers, many of them shallow. A typical jet boat can go through 3-6 inches of water (or less) when on step.
However, this is jetboating to the extreme:

http://www.racerxsprint.com/theboat.html

950 hp, 480ci, methonal-injected, 0-85mph in less than two seconds, 8 g in the corners.

On the water!!

I want one!!