What's the best material for a deck?

[oldbluesplayer]

for what it's worth, when I redid part of the floor on my 20' Seafari, what I found for original core was 3/8" plywood in 6" squares, under the seat pedestal, and 3/8" end grain balsa core all the way back from that. I took off the top skin with a circular saw, set for a shallow cut, took out the wet core, left the inner (lower) glass skin in place - then glassed in new 3/8" plywood, then reglassed the top skin back on, and seamed the cut lines.

The result is solid as a rock - I think the key is the glass/core/glass sandwich construction.

Bill