Ground out a big chip in my gel coat where the deck curves down to meet the tapeline/hull. Lo, what did I find? I ground out about 6"x1/2" of gelcoat until there was no gap between the gelcoat and the fiberglass. now, the tricky bit is building up the gelcoat until it's the same level as the surrounding gelcoat.
Sigh, lots of layers and mixing. I hope tomorrow evening to be able to sand it down.