My first ding repair was to put this fin box back in this Force Field rescue board oh so many years ago. I just cleaned up the foam and epoxied it back in place again with some cabosil and such. Didn’t really tie it into the glass on the deck or anything. Just put it back like it was originally.
Looking at how The Board Lady does her fin boxes, I went, “Duh. Why didn’t I do that?”
It came out again last summer. Had some balsa around, attached it to the fin box, opened up the hole in the bottom of the board to match… I was sooooo tempted to use carbon for this just for bling, but went with some 9 ounce 8HS weave under the box and into the board, wrapping up to grab onto the glass on the bottom, and 10 ounce plain weave over everything and out another 1/2 inch or so past where the inner layer stops.
Hopefully it’s bomb proof this time… or at least lifeguard proof. 
Patrick
