Correct way to fill in a thru hull hole

[FishStretcher]

Well, that makes the grinding easier. Looks like I will have to try some vacuum bagging this spring. I am thinking grind it and wet layup patch half thickness from the inside with a ~1/16" polyethylene sheet backer, then vacuum bag inside and out. Once that cures, grind the outside, wet layup and vacuum bag the outside. That way I can keep the hull shape with the polyethylene backer.