I'm a newbie to hull repairs, and to quickly describe my repair i have some hairline cracks in the front of the starboard hull (my plans for repair are described in more detail in my previous post). If I was to try to grind through the gel coat on the hull to make some repairs with epoxy and glass fabric would I hit foam before I hit structural material? I'm familiar with the fiberglass foam sandwich construction, but I guess I'm unclear as to if there are in fact 2 layers of fibergalss with foam between and gel coat on the outside of the outer layer, or if it is just an inner layer of fiberglass a layer of foam and gel coat over that? What should I do?

The Yooper