I've used aircraft polyester for a boat (see link). It's shrinking ability was amazing. The nylon does seam to relax a bit. I have tried wetting it before heating and that does seem to make a difference.

: I have been told that nylon tends to stretch back. From the photos of the
: boat right after the skin was shrunk, I thought it was a polyester.

: I'm looking for skin options for my next SOF. Most of the polyesters are sold
: preshrunk - and can't be shrunk again after they are installed on the
: boat. The exception to this are the lightweight aircraft fabrics. I used
: the 3.7 oz on my first SOF, but I would prefer something more durable for
: the next boat. From your photos, I thought you might have my answer. But
: if it doesn't stay tight...