Jim, that's gluvit you're using (or an alternate named product). Great stuff and makes the bottom glassy smooth. I know what Josh post was stating about not having to reapply and hitting rocks leaves the coating. But we're in the PNW, where we have glacial rivers and LOTS of rocks. So scraping bottoms is what happens. And dragging boats is a common practice. I know moving my buddies 18' willie with gluvit bottom over rocks was NICE! Was like it was almost on wheels (and I say ALMOST). Yeah, you have to reapply, but it's worth the money to me. I'd have to look into the smooth Linex. But with weight in the boat scraping on a rock, I wonder how "smooth" it'll respond going over it. I've only dealt with the lineX in my truck, and it's a BEAR trying to move stuff in and out of it. Protects the bed, but getting stuff in and out of it is a pain to slide. But it's the rough stuff. Maybe I should have it taken out and have smooth reapplied. It's a good 10+ years old and looking pretty rough anyways. But would love to get some actual on river experience of our rivers with the lineX bottoms applied.