Interesting. Is it a sailing or motor race - those boats go both ways. How large an engine is allowed?
You may find that info here...
http://crabskiff.org/main/page_home.html
or here...
https://www.facebook.com/Smith-Island-Crab-Skiff-Association-295269101404/
No help that I can see, but interesting. I'm sure it's a hoot for everybody involved in this festivity.
It's straight-up powerboat racing, with several classes ranging from "1800s stock construction" to "as light as you can build it". All race boats are required to stay within the limits of 625cc v-twin air-cooled engines (Kohler, Briggs, Kawasaki, etc..like the lawn mower racers use), nominally 20HP. Of course there's a lot more power coming out of some of 'em.. ;-)
It's a blast.
Good site with great pictures...
https://www.twistedoysterboats.com/