sailing fool you would have had a cow if you saw the side of my boat. at the water line it had a 10 by 18 inch area of the gelcoat scrubbed off. after grinding it back to good glass and further i had a 24 by 36 inch taper that was in the center 12 by 18 area was just the last layer of glass . i left the last layer to have something to lay the new glass on. the repair has held fine including when i had to beach the boat and it laid on that side on the repair.
its not hard to do, if you follow directions.
jas i even have some of the strong filler left to thicken the epoxy with, you wont need much, so let me know if you want to do the repair i can give some to you