Most likely you will have to sew up your own..I have not been able to find any of these locally and I guess my next search for the material will be a boating shop or nautical supply store. My guess is they are available but only in upscale stores, which we definitely do not have access too..lol.. Possibly a fabric store will have the canvas, then you have to have the correct needles, thread etc. sounds endless acutally.. Maybe upholstery shop could make you one, using the old pattern as the guide. The more I think about it I would go with upholstery shop first.