Since we're talking about coolers here, I have a question. Inside the icebox, fore and aft, there is a little ledge several inches from the bottom of the icebox. A few years ago I recall seeing another J/30 that had a shelf sitting on those ledges. The shelf was made of plexiglass with a teak rail on the inboard side. I was wondering if this was original equipment, and if so, I'd like to have a replacement made. Can anyone describe this shelf better? What are the dimensions? Thanks!