It's also wider. By almost double. 15' beam. And it's almost certainly made stronger since it's an ocean-going vessel. Much stronger. And I doubt that little go-fast boat is sporting twin QSX Cummins.
I used to eat, live and crap boats. That little POS is NOT anywhere near 35,000 lbs. It's lucky if it's 20k and the trailer (it's called a 'quad' for the 4 axles) is maybe 4k. Looks aluminum to me. At least the front does.
I don't know where the Trooper got that 37k number. Maybe he looked at the Trailer's GVWR, the Truck's GCWR, added them up and came to the conclusion that the guy need a CDL to pull something that size for hire. Which you do.
Which is why so many hot-shotters use HD 2500/250 series. They're not as capable but the GVWR on a 2500 is 10k (that's changing, too) so you can pull more load. Up to 16k, without a CDL and all the other happy horse-manure that goes with it. You use a Class 3 (F350/3500 series) and the GVWR is 14k, which limits you to 12k towing. 26k GCWR is the magic number. Weird
RV's are exempt for personal use. And the last I checked, a boat is sure as heck an RV.
This is boring and I'm gonna get in trouble trying to educate people. I know what I know. I just don't know enough to be able teach it.