So exactly what are the rules

Under Australian Power Boat Association rules

• All boats are limited to 8.36 litre 4 cycle 2 valve per cyinder engines and superchargers are allowed without limitations

• All boats must be a minimum of 6.4 meters (21') and a maxiumun of 8 meters (26' 3") long and a max of 3.81 meters (12" 6") 'wide.

• All boats must weight at least 910kg's (2000 lbs) for unsupercharged and 1080Kg's (2381 lbs) for supercharged engines

• All boats must have reinfoced cockpits for driver safety

• All boats must have onboard fire control systems

• All boats may use petrol or methanol (alcohol) fuels

And thats pretty much about it

American & Canadian Rules differ only slightly