Hooper,
I had the same bi Fold panel and replaced it with white starboard.I ran it over the table saw and put a couple of 1/8 in grooves in it for a pattern. I didn't use hinges because my livewell was in front of it but instead used slide bolt latches so I could remove it easily when I needed to. Heres a link to the pic.
http://www.theboatzone.com/gallery/album06/livewell
Dave.
It was 3/4 inch board. Starboard also is made in XL or extra Light. About half the density of the regular starboard so less weight. But the edges don't show as clean due to the micro air pockets along the cut edge. The XL is good to use in 1/4 and 3/8 where you don't really see the edges.