I see no pictures. But anyway, if you're beaching the boat a lot, then sure, put a few layers of glass over the bottoms of the hulls. Cut some strips maybe 4" wide and as long as you think appropriate, soak the first one you apply in epoxy and place it along the hull. Subsequent ones don't have to be pre-saturated; after you position them then dab more epoxy on with a cheap paintbrush just to make sure they're also saturated. I'd say 2-3 layers would be plenty.

While you have the boat upside-down and the epoxy out, run a bead all the way around the hull-deck joint to seal that as well.