Matt,
If polyurethane it takes a bit of work to fine rub as it is very hard. But if you do you will see anything corser than 2,000 grit in the gloss. If really pushed you could do
1,000 as the scratches left are not too bad.
600 is easier but you pay fot it in drop in quality of the finish.
Takes about 16 hous to wet rub.
4 hours per side per hull in 2,000 grit.
I'd still buff with light cutting compound or polish with alight cut in it.
Stay away from the gunwales with both or you'll go through the paint quick smart.

Hope it helps.
Regards,
Phill