I have been using Aquacote clear as a finish on my kayaks for about 13 years.

http://boatcraft.com.au/Shop/index.php?main_page=index&cPath=5_38&zenid=83a04252977a72cdd511e2a7f76ed3d7

It isn't easy to get a really glossy finish, but that doesn't worry me as I prefer a satin finish.

It is harder than other finishes and does a good job of providing UV protection.

Advice from the distributers and my own experience is that after a couple of coats to build up some thickness, subsequent coats should be progressively thinned until you get to about 50% water/50% Aquacote. That makes a big difference to the smoothness and glossiness of the finish.

I have always got best results if I can apply in cool conditions, but then fairly quickly have the temperature rise so that it dries before the cross linker loses its effect. I apply it in the shade and then move the kayak into the sun.