Re: Badly cracked Gel coat - only below water line
I repaired some cracks and gouges on my 88 four winns.
with the gouges, they went through the gel, already had a vee ground in; I used gel coat patch on 1/2, marine-tex on the other.
I like marine-tex better, easier to work with, ( epoxy, and you will be painting, no worry about poly sticking) (if prepped good, poly will stick to epoxy).
With the cracks, I think you need to grind a vee groove in them, to get a good base to adhere to.
drill a small hole, just barely through the gel coat at the end of each crack, in order to relieve the stress from moving further.
And poly needs wax, or a covering in order to cure. A blush epoxy needs sanding.
I like epoxy.
