I built my wife a sea rider last summer and I was afraid there would be ware down the keel line from all the crushed shell on many beeches here in florida. I put Gator Gard (truck sprayon bedliner) on with a brush about 1/2 inch wide the full length of the kayak. You can get this at a auto paint store. I also put this on the end of my Greenland paddles. This really worked GREAT and is damage proof and doesn't add much weight. Give it a try. Just a idea....kirk