: Nylon seems to be the most popular skin. Good and tough but not a
: lot of coatings will stick to the nylon. So you are sort of
: limited there. Plus nylon is hygroscopic, meaning it absorbs
: water and when it does, it expands. That means it loosens and
: wrinkles on your boat. (yes, it does it even after it is
: waterproofed) Once it dries it goes back to drum tight. Some
: people have been able to get it tight enough it doesn't wrinkle,
: I have not been able too.

I used 7 Oz nylon on mine (I think, weird imperical measurements :P) and the only wrinkles i have are around the coaming.

as for sealing it, I used a standard urethane based boat varnish (no mixing or such, just a can of viscous fluid i applied with a normal cheap brush).

I haven't had any problems with leaks, even when I ran into unexpected headheight waves and was smashed onto the rocks of the pier and had to fight the incoming waves to get my kayak up out of the water. (scraped the paint a fair bit, but with 3 layers on it didn't leak)

http://matthias-kayak.blogspot.com/

(I realise now that it looks a bit wrinkled in the first picture on the blog, but i haven't noticed it before now, so it's mostly just the light hitting it i think.)