I've done some fiberglass repair on boats, but we always did the repair from the inside with a form applied to the outside, so you could get a good gelcoat finish and just clean up any oops in the gelcoat with gelcoat paste. You'll have to use some kind of backup in the hull to backstop the repair whatever you do. Some expanding urethane foam might help. I'd be sure you got it real clean to remove any wax and mold release agent, and bevel the repair out wide, since the first bond is mechanical, not chemical.

In any case, I'd pass on that one. I hear Puakea designs are a little fragile..