not the seat, the rail cushion
Thanks for your reply. What I am wanting to make are the cushions for the curved stern rail. These are made using 1" pipe insulation covered by a suitable material (sunbrella) and closed by a velcro strip. The reason I asked for a pattern is that the sunbrella material will not just wrap the foam insulation in the curved shape without puckering, wrinkling, or folding. You can see the cushion I am speaking of in the link photos you provided.