I have to admit, drilling a hole in the hull of a boat is not a good feeling. I drilled a hole in the bow and stern for a grab loop. I had glued a wedge of hard wood to the inside of the hull. this should keep it rigid and water tight. After fiber glassing both sides of the foam, Martin helped me glue them in place. We had to work fast using a caulking gun to lay a bead of epoxy along the seems. I'm not really sure why it's purple.