Something has placed a hole in the bottom of my boat. Hole is about dime sized in diameter and is below the waterline. Surrounding fiberglass is in good condition, with the glass that was damaged still attached on the inside of the hole. I cannot access the backside/inside of the hole. Can I just patch with marinetex? I haven't ever used the product before but wanted to know the limitations of the product before I try it. I plan on using a wire brush to completely remove any loose glass, sand about 3/4" around the perimeter and push the marinetex well into the hole, and smooth out to overlap the hole. let it dry and the sand. Will this work?