So check this one out,did it for fun as I do this for a living. It's 1/2" marine ply which is Duglas fir with a better adhisive, ext. is the same but has voids marine has none. It has 1'x1' ribs to make it stronger they are oak and about every 16" the conners are Mahogany as is the door at the rear. The lid opens with a hydrolic piston so it will stay up. The bottom has cedar 1x4 planed down to 1/2' across the 1x1's so as create an air space to keep the sails out of any mositure on the bottom, lets the air circulates around the sails or what ever is inside and is lite as it is heavy enough, also helps keep the bugs out, not that they can get in but you know bugs, a little over built but it will last a life time. The thing was coated with west system epoxy and the 207 or 205 hardener can'y remember it's there best hardener with the UV protecter about 4 coats sanded between each and buffed after but be warned it must still be covered or the sun will eat it up as it did the first time I could paint it but wouldn't be as pretty I'll try a clear allgrip next time and see what happens.