The main issue with any coating/skin combination is whether the coating is as flexible as the fabric. If it's not, the coating will eventually relieve the stress by cracking or delaminating. Nylon stretches about 300%, polyester about 24%, cotton canvas about 10%. By comparison, red oak's maximum seasonal expansion is around 3%, so putting a coating that's intended for wood on nylon probably isn't a good idea. The secondary issue is whether the coating you choose will stick to your fabric. If it doesn't you're looking at eventual (and inevitable) delamination.

So you have two choices- match your coating to your fabric, or your fabric to you coating. The top choice for nylon (or anything for that matter) is Coelan Marine Coating, which flexes 300% and sticks very well to nylon. Has been used with great success on SOF kayaks. Comes in lots of colors. One-part, easy to apply well. From there on down, things start being a compromise that you have to make decisions on. Corey's Goop is tough, but the two-part is touchy, and most people have trouble making it look good the first time, and it is prone to other application errors like having it on too thick and causing foaming. I talked to the manufacturers of Pettit, Epifanes, and Interlux, and the only one that would recommend anything was Epifanes. They said that their traditional varnish was the best of their products and would work fine on any of the fabrics, but best on canvas, but that they wouldn't necessarily recommend it because it has a 3 week cure time under ideal conditions. Their next best recommendation was the monourethane topsides paint. They stick great to synthetics. It gives up some abrasion resistance to their two-part polys, but they felt that flexibility was more important than abrasion resistance, so they would chose the more flexible monourethane. To maximize your durability with this type of coating you have to start thinking about switching from nylon to polyester or cotton, unless you don't mind reskinning frequently, which has its advantages as well.

Of course- you can always use reinforced vinyl fabric, which doesn't need a coating.

Good luck deciding! It's the toughest decision you have to make when you're building a skin boat.

m