Does anyone have any experience with fixing deep gouges in the gel coat? Looks like my fender hook got caught between the dock and the hull and put many deep gouges and scratches in roughly a 2x3 foot section of the hull. In one spot about the size of a quarter it's right through to the matt. I figure this will require some sanding and resin, etc., but what type of grit for the sanding? Would a vibrating sander or rotary work best. What is the best process. This will be my first shot at a significant hull repair so any help anyone may provide is greatly appreciated. Thanks in advance! Rich