West Systems makes an epoxy especially for HPDE boats. I think it's called g-flex maybe? Not sure how expensive it is.
That "repair" doesn't look like it is holding much, I would remove and then re-repair. I fixed my huge trashcan with a blow torch and a 1/2" screwdriver. Would probably work on the boat bottom. Basically you heat the screwdriver and then use it to "weld" the crack back together. Don't just smooth across the surface, oush the hot screwdriver into the crack to get both sides good and hot. They will fuse back together if done right. This method doesn't cost much at all, just the propane for torch.