It is much lighter than cotton canvas. It also should not have the issues with rot that canvas boats tend to have. I have heard from several sources that, in general, canvaas boats need to be re-skinned every few years. I am sure there is great variation due to care, location and frequency of use. The #10 Duck may be more available in your area, but in the age of the internet, that is not a show-stopper issue. Tacoma Tent, Dyson, etc. all do mail order. I think the poly canvas, being less absorbant than the Duck, may require less coating material, though most people that I have heard of using Duck, also tend to use house paint as a coating.

The only way to truly make a judgement is to make a boat (or two) using each skin material, then make a Tom Yost folder with a PVC skin and subject them all to exhaustive research. "Honey, it is not that I want to, but it is all in the name of science."

If you would like, I have some scraps of both the nylon and the poly canvas that you could play around with to help with your decision.

Regards,

Marcel