Upholstry
You can do the job for much less money rather than ordering "Marine" quailty upholstry. You can get any fabric at any fabric shop. I would get new DENSE foam. Then take it to any seamstress in your area..(or maybe a friend). The difference is that you should use plastic zippers or stainless snaps if you prefer. Scotch guarding them is a good idea. Remember when doing the scotch guard, put a tack coat on first, before giving it a good coat. I bought an industrial sewing machine 3 years ago and did all my own work. It was easy once I got the knack. When I was done, I sold the machine for almost what I paid..It really wasn't difficult!!