Why paint? Ever herd of this, got one on my boat over twenty years now.

https://www.gator-guards.com/

There have been very reputable accounts of professional builders using truck bed liner inside wooden power skiffs. Can’t say I know of any applications on the outside. I cannot say if that’s because it is a bad idea and no one does it, or whether I just don’t know about those cases. FWIW those insiders aren't outsiders.

The rough texture of truck bed liner paint will hurt performance.  How much it will hurt is the real question.  Another paint that you may consider is Wetlander.  It is designed for airboats and supposedly very tough.  A friend of mine uses it on the bottom of kayaks that he sells.  I am going to use it below the waterline on the skiff that I am currently building.  Yet another choice is KeelEazy.  I used it on the bow/stern my wife's Frej and it has held up well.

   I recommendbeach rollers. There is no need to scratch your hull at all. I use the corrugated pipe shown on this thread:

http://www.clcboats.com/forum/clcforum/thread/30201.html

Mike,

I know that Sam Devlin of Devlin Designing Boat Builders sprays truck bed liner on the interior of some of his workboats. I'm skeptical that the material would work well on the bottom/exterior. I don't know about its water absorbtion when immersed, but the texture is probably problematic anyway.

If I were you, I would want to water-test a sample before applying it to my boat.

Cheers,

Dick

Well thanks for all the replys! I have orderd some Keeleasy!!