Dave,

Looks like a big job....Grind away all cracked glass, look for any cracks or dis-color then build it up new. Build a 12-1 taper from the good glass to the "hole". I'd make a mold from the outside of the hull just to the side of the damage, where the hull shape is about the same. Wax the hull or tape wax paper to it and lay one layer of cloth. Wax or use wax paper on the inside of the patch then screw the patch in place on the out side. Just one layer will be flexable enough to shape over the hole. The screw holes can be glassed from the inside and filled from the outside.

Glass up against the patch tipping the hull so the patch is facing down so gravity will hold the glass is place. Overlap the hole by a good 8". Use a biax to spread the strength out on all directions. The last layer of cloth should cover everything and I'd go 12" around the damage. Remember to use enough resin to wet it out but the higher resin content to glass the weaker in strength. Use a spreader and a glass roller that help to move the extra resin to the side . Once the inside is done then you have to blend in the outside and make it pretty. Take off the patch grind smooth after you clean off the wax (or use wax paper).

I cut big hole in the repair job on the G-Cat. Take a look at it and the SuperCat both on the upper left on projects. http://www.themanshed.net

Mike