Is there a product out there that covers and protects boat mattresses? In my case, I just bought a new Beneteau 31. While the cockpit cushions look spiffy, the fore and aft mattresses are just, well, naked mattresses. They're, of course, in dimensions that are non-standard to the outside world. Sure, I could measure the hell out of them and get something made up, but is there an off-the-shelf product that already does that?