Practical Sailor just did a full blown article on interior cushions, and sometime last year Good Old Boat did an article on fabrics to cover them with. PS gave names of companies that specialize in cushions alone. The best was in Michigan as I recall. They use a special high density open cell foam. When I replaced mine, I took them to a local auto upholstery shop, picked out a high density foam the same thickness as my originals, then they took the old original foam, cut the new cushions using the old as a pattern, and covered with an auto upholstery fabric on top, and vinyl on the bottom. The vinyl bottoms keep them from getting wet from any leaks or condensation that accumulates on the berths. While the auto fabric is rougher to the touch....I figured that auto fabric would be more durable than the interior stuff used on furniture...and was also UV stabilized. It has not faded a bit. I leave them stored on edge to keep any moisture from being trapped beneath them, and to let them breathe. About 4 years now with no problems. Cost was less than $500. Two sleep systems to go with these. If it's hot...a sheet on the bottom and nothing on top....or I have a jumbo sized beach towel to use as a blanket. If it's running cooler.....I keep my Wiggy's sleeping bag on board. The Wiggy bag will work even if wet and dries out in a few minutes. Howard