The Line-X style bed liner product is used in the driftboat  world to
armor boat bottoms.  Seems to work well.  Here's a link to some of the most
beautiful boats being done right now by a guy in Livingstone, Mt.  He uses
one type bedliner inside that is softer and one that is quite hard on the
outside of the bottoms.

  There are about a dozen different brands available...some are even
'franchised' and require you to have them applied by a guy who's paid the
Vig to the company...those brands don't seem to be any better than the
self-applied ones you can do your self...or so the rap goes on the various
internet forums about that stuff.

http://montana boatbuilders