My opinion ... patching fiberglass and remodelling the interior are minor
(almost cosmetic) repairs (not major). Major would include engine, outdrive
if that's what it has, stringers, other structural and more on a larger boat
.... and those repairs cost big bucks for parts and require significant
skill/tools to do yourself. And then there could be that structural part
that you can't see, and can't repair. So, what type of boat are you talking?

every bought a boat that needed some major repairs, like patching a bad
spot in the fiberglass or remodeling the inside?