I agree with what others said... Get a sample first and post the source if possible. I do quite a bit of hobby sewing (backpacks, bike bags, sleeping bags, etc.) and have never seen anything similar to what I buy from Dyson. I would also worry about DWR coatings(durable water resistant or something like that, they make water bead and drip off) . If its any quality and intended for outdoor use, it very possibly is lightly coated with poly or coated with DWR. Once you get your fabric, compare it to scrap from one of your other boats, if it resists water the least bit, it will probably do the same with poly.
Or not...
Scott