Bottom Gelcoat Repair?

One of my winter projects is fixing up GF's 1958 Glaspar Sport Lido. Cool little boat we dock hop with. Putting in a new floor and painting the boat. I removed the deck and have the boat flipped. Bottom had years of bottom paint on it that I scrapped and sanded.

The gelcoat is cracked all over where the bottom paint was. Any suggestions for recoating or will the cracks just come back short of grinding down to the fiberglass. This is a knock around boat but want it to look decent. Any suggestions??

Thanks

From the loks of the one spot you're showing with the longitudinal cracks, I'd guess that's a point running opposite a reinforcement and the bottom is flexing. If the reinforcement attachment is loose or insufficient, whatever you repair will come right back.

Each of those cracks is going to need to be dug out and filled before overcoating with new gel. If not, those crachs will probabaly reappear very quickly. Trying to sand the gel completely off and end up with a flat surface is going to be almost impossible.