I purchased a Quest for fishing my favorite river. It is a limestone base river with class I,II and III's; many butt scoots, boulder gardens and a few drags. This is my 3rd yak; I have 2 Old Town Loons with a sacrificial rear keel that addresses part of this "wear" problem. I spent hours and hours trying to find a way to save my $1300 watercraft and plastic welding seemed to be the only viable solution from the (this) manufacturer. There is another solution, however, that has worked on this linear poly boat. While not a "permanent" one, in that wear will still take place, it has proved to be a better solution over welding on the boat over and over. Old Town sells an epoxy based repair kit that worked well in a repair that I did a few years back. They were out of the kit, on backorder and really expensive ($40 rings a bell) for about a pint of the stuff. A neighbor offered me another solution - a poly based 2 part epoxy mix. With the boat properly prepped and applied, this stuff just kicks butt. If I can save you an agonizing time going through what I've experienced, just let me know. I've written a step by step procedure for this that I'd be happy to email you, complete with pictures of the process.
SIDENOTE: I must admit that after all the research on a new yak prior to purchase that took me 6 months, the interpretation of the fine print at the bottom of the Quest sales page went right past me. Something about "Live Longer, Hobie not intended for use in rapids or heavy surf." The jist of that fine print was "wear a life jacket", not "the boat will wear out". So while I'm pulling my hair out trying to save my investment, the response from Hobie is "didn't you read the fine print?" That is expected from my insurance carrier but wasn't expected from my pleasure craft manufacturer. In Hobie's defense, however, I will add that Matt did send me some plastic strips to weld on. Also, I absolutely love the Quest for my application and fishing pleasure. There are some engineering improvements that could be done to make it a better boat but that's another story.