: Hardware stores sell that epoxy repair stuff that's like a long
: tootsie roll with half hardener and half resin.

: You kneed it together and it starts to kick. You cold fill it with
: that and in 15 minutes it starts to stiffen up and you can shape
: it with your fingers.
: I've used it and it hardens like stone and you sand it later or add
: a little more. Very easy to work with to create shapes.

: I agree with Nick, some enamel paint over it and it's done.

I could do that, but I really want to bite into it with my dremel tool. The boat has already drawn blood, and I want my revenge.
There is a lot of void where the slider groove meets the deck, and I don't want to have to do another fix the next time I break through the gel coat.
I also don't want to change the shape of the groove by sanding away the gel coat and leaving it - the void is about 1/4" deep - the slider would not act smoothly with that much removed from the corner.