where can I find some grey material that warlock used for the rear seat on my 1990 25' Cat, its not vinyl, its some kind of cloth

The cloth exposed to UV did not last long...my boat is older than yours...cloth went in the dumpster in 1994.
Seemed like no one had it at that time or no one put it back in because of problems with short life.
I replaced the entire interior with vinyl. The cabin cloth has held up well however.

The cloth that Warlock used on my 1989 offshore did not last very long, I changed the entire exterior seating area in 1995 to a marine vinyl which I still have today in very good condition. My below bow interior is still the original cloth and is in very good condition.

ok, thanks for the input. looks like a nice winter project !!!!!

I just bought 10 yards of that yacht cloth from Bill Sturgis at ARKO Upholstery for my 1990 23' Warlock. If you have the dark grey cloth that reminds you of burlap, the color is called graphite. He sent me the 10 yards for $200 + shipping - very reasonable in my book. Here is Bill's cell number - 801-360-0658. By the way, it is a perfect match that I plan to use this winter to redo some of the upholstery in my boat. Bill in Texas