Electric Comet wrote in
:

i always thought that any racing sport should have an unlimited class
competition

As desirable as that is, eventually you run into the twin
problems of it being too expensive and too fast for safety
on any available course.

maybe just have some very basic criteria like has to have at least 2
wheels or must have a sail and a hull

Pretty much all forms of car racing require exactly 4 wheels,
and they have to be on the 4 corners of the car (this rule
being because someone built a car with 3 wheels on one side,
and 1 on the other).

i thought drag racing with funny cars and dragsters were unlimited but
maybe i misremember

No, drag racing hasn't had an unlimited class since the
50's (or maybe early 60's). The only unlimited class I
can think of would be LSR at Bonneville.

John