In my opinion : It's sounds exactly like the damage you would typically see from a very hard grounding. I've seen it on several occassions in our boatyard here - on several different makes of boats. I've never seen that on a C27, but I have seen something very similar on other boats.
The damaged area need to be ground out and reglassed with new laminate made of glass, mat, and roving. This is not a repair that can be done by a beginner and have the boat be sea-worthy. It's important that the repair be properly designed (with the right number of layers of cloth of the right type, with the fibers aligned in the right direction... not too thick, nor too thin, nor too stiff/strong) . It must also be properly bevelled into the original laminate to adhere well and to flex properly so there aren't any stress fractures in the future. Repairing that crack can't be safely done with resin. Plain resin or marineTex is too brittle and will crack almost immediately. Even without seeing it, my experience tells me that a proper laminate repair job will take at least 10 hours of labor, plus set up and clean up time. Then add time for fairing and painting the repaired area. Plus hauling and launching. I wouldn't be surprised if it took 30 hours. Fair winds, Judy B http://www.blumhorst.com/catalina27/catalinahomepage.htm
