Are you sure that is paint. It looks like delaminating gelcoat
. Pull off a piece. If there is fiberglass
stuck to the back of it then it's gelcoat
. Either way you'll have to strip it down the the base material.
If the boat stays wet all winter, that's not good. Polyester resin absorbs moisture.
I'd redo it in an epoxy/glass coat and then repaint with a marine
quality paint. And at least put a tarp over it when not in use. The worst thing is, if it's wet and freezes, then it peels up more and more of the coating with each freeze.