I am sceptical of "UV" filtered resins for surfboards. I've seen specifications of 1000 hours of UV exposure. While this is plenty for a foam surfboard which is basically a disposable item, but it isn't that great for a kayak. Again, if you are going to be careful and protect the boat in other ways you can probably get away with it, but I would still want a UV protective finish over top.

1000 hours is very low for the tech data I've seen. The newer resins have much higher ratings. I would not recommend any of these as the final finish for a kayak that is stored outside. It totally depends on how the final use of the kayak. For the interior of the holds or other areas that rarely see any sunlight? You don't need anything else. Racers are a strange bunch... You can preach to them about improving the engine and using a heavier boat but if they can save a couple pounds (heck, ounces) they will. Most people who race are like that, myself included (a few road races). A quart of paint or varnish is usually used to finish an average kayak. That's two pounds of weight. For racing kayak that will be pampered off the water why not save a few pounds of weight by not using paint or varnish?

I am also highly doubtful of any "slipperiness" qualities of graphite in a finish like this with respects to skin friction against flowing water. For it to do anything it would require enough friction to actually slide graphite molecules off the surface of the boat. Slippery against rocks, maybe, against water? highly doubtful.

I am also doubtful against water but I have heard the claim from racers. Some believe it works. Who knows... I know it DOES work against rocks. Adding graphite makes a more durable final finish than most paints, varnish or plain epoxy.