: Actually I'm more interested in resistance to abrasion, ie: damage from what
: you didn't see under the water. The resin/silica/graphite mixture seems to
: be highly abrasion and damage resistant. How much of that is from lubricty
: I can't tell.

: Bill H.

Bill, abrasion is also a function of pressure, at some point the slipperyness of a few mills of coating means less than the durability of the underlaying skin below the coating. When I look at the bottom of a kayak where there's substantial gouges it's because there was substantial force behind it and the gouge breaks the glass as the underlying wood compresses more than the glass.
As long as all contact with rocks is a sliding motion then a low friction surface can help but when a kayak lands on a rough surface it's the glass skins ability to not compress AND the characteristic of the individual fibers to an abrading force that matters.

I'd be curious to see tests that simulate sliding impacts with 250lbs of force across a sharp rock in order to see what is effective for durability. The damage I see isn't from dragging 45lbs of kayak over a log but 250lbs of kayak and paddler LANDING and sliding over a rock.

Seems to me the kind of abrasion resistance that matters is the kind that protects against the most significant damage, sliding impacts that compress the underlying wood. I don't see resin coatings having as significant a factor as the weight and type of glass within the resin.