I have not tried it but plan on spraying the bottom of my TDB with paintable rubberized undercoating at the water line. The undercoating is much lighter than the bedliner material and is certainly not quite as durable. I got the kit that uses a siphon gun so it does not have all the VOC's of the aerosol cans. If/when I get to it I'll be sure to report back on how it works. The concrete, rocks, gravel and clam shells are starting to take a toll on the gell coat. I kinda see this coating as a consumable item, not a "cure".
Gene