I killed an afternoon fixing a crack in the hard-bottom dinghy transom. It looks like someone removed the backing plate and motor mounts have cracked the fiberglass. It didn’t really need to be repaired, but is seemed silly to not patch up the crack as water will continue to get in and if left outdoors for the winter, it will eventually split the transom with freeze thaw cycles (maybe). So I guess it did need to be fixed.
I opened up the crack with a chisel then beveled the edges with a grinder (not shown). I used up the white gel coat left over from the big repair and added some regular resin and colloidal silica to thicken it. The garage was cool and I needed to put a space heater on it and warm it with a heat gun to get the resin to kick.
I would have gone over it all with a beauty pass of white gel coat but I barely had enough to do the repair. As it was I had to open the can with a vise and slip jaw pliers!
I fashioned a motor-mount board out of a dollar-store cutting board. I gave it a quick sand, polish and coat of wax. Yes, this job was cheap and dirty.