I've used a water based finish on my first Snowshoe14 and am about to
use the same on my second. Here in Australia I use a product called
Aquacote, distributed by BoatCraft Pacific. It's described as "a
water based two pack Polyurethane Topcoat - Clear". It claims good UV
resistance with three coats.
I tested both oil and water based finishes and was unhappy with
the "yellowing" of the Dacron with the oil based finish. The water
gives a really clear finish and highlights the translucency
of the finished Airolite.
If this is your first go with treating Dacron may I suggest the
Use a foam roller and tip off with a brush as you go. Go light on the
first coat. You don't want too much liquid on the Dacron and you need
to avoid it pooling and soaking throgh the weave to the other side -
less is more sort of thing. Use a light behind/under where you're
working - makes it very easy to see where you're up to and which
spots you've missed. Have a "spotter" looking over your shoulder.