So...

I built decks 2 seasons ago, and they have warped quite a bit...

Before:

After:

Ok...

So, I was thinking about taking the seats out, designing a professional deck setup.

A. Has anyone done this?

B. What metal material should I use? (Stainless)...?

C. What thickness

D. I know metal will last a lot longer, will it weigh less=faster boat?

Thanks much.

I'm currently doing the same sort of thing with a flat bottom jon boat. I cut the seats out and am getting some angle aluminum welded up with a small piece of 1/4" sheet aluminum on both ends of the angle stock.

I am doing this so that i can aviod more welding by simply bolt it in to the boat, not to mention that i feel much better about bolting something in rather that trying to have the thin sides of the boat welded and then expecting them to hold up under constant stress.... welds do break contrary to popular belief.

The first jon boat i owned I went out in a lake when it was really too rough to go out and ended up having the section of the bow break on me (the part where it starts making the curve toward the bow that's welded) About a 5" section split right down the middle of the weld If you feel like really spending some money you can use either aluminum or staniless steel to deck it out. This would defintly make it lighter but that is seriously going to cost some $$.

IMHO i think you would be better served to cover it back with plywood but make sure that you do a better job and sealing the wood from moisture. If it is going to always stay outside I would use some sort of liquid plastic type wood finish that would permantly solve the warping problem.

If you have deep pockets then i say heck yah go for the metal option! You may have to do a little more framing with the angle in order to keep you from having to buy a really thick (and expensive) sheet of metal. Not to mention avoiding the dreaded "oil can" effect when walking on it but once you're done the only thing you'll ever have to replace again would be the carpet.

.125 sheet aluminum minimal with bracing 16 on center  

Anyone know how much 2 full sheets of 1/8" Stainless costs??

I was lookin at a site, it said like 450 for a sheet...

I'd rather just buy a glass boat w/ a 40 horse and 2 councils if thats the case

No, you don't want stainless.  Too heavy, hard to work with (isn't very forgiving) and all.  Stick with the .125 aluminum like Catt mentioned.  .125 (1/8 inch) thickness, 1 1/2 inch angle should be okay for your structure.  

Find used aluminum.  Head to your local scrapyard, and see what they will sell ya.  I get cutoffs from large factorys, sometimes a full 10 feet long, and 3 feet wide even, in all shapes and sizes, and thickness etc, for 2 bucks a pound.  The honeycomb is real nice, as it is light, but incredibly strong, so it is dirt cheap, due to weight.  Got a load of some 1/16 honeycomb last Saturday.