has anybody here ever used synthetic wood for making a boat deck?
 

My nephew has the oppertunity to by a 1978 Glastron V178 with a good
115 hp Evinrude for cheeep ($100.00) that includes the rinkydink
trailer too!

The seats are crap and the floor is absolute junk. the former owner had
the engine serviced and winterized about 7 years ago. the carbs are
full of sea-foam, and the compression is tight.

OK, coming up with seats is no problem, we have access to a wide
variety from compact cars at an auto salvage for $10 bucks a
throw...(hey! he's a teenager!) but the deck is the problem. I told him
I'd help him work on the flooring which isn't too complicated. Believe
it or not, the stringers are ok. just some minor rot in non strategic
places. I probed around to see what I could find, and they seem fairly
sound.

Instead of using plywood, i thought of using synthetic. When we got our
house about 11 years ago, the front porch was rotten so we had a
carpenter me do it...out of salt treated tongue&groove pine. What a
mistake, that only lasted a couple years before it got soft and started
to crater. and seeing it's a big job to pull the pillars and brace the
porch roof, and I didn't want to do this ever couple years , we settled
on synthetic plastic lumber, like this:

http://www.epsplasticlumber.com/lumberpricing.shtml

I've really been impressed with it. sure it costs like heck but it
hasn't shown any signs of deterioration, and I think is way cheaper in
the long run than using regular wood. The guy installing it said he had
never worked with it before, but after a bit he kinda liked it and he
did a good job.

I have several boards left over because the hardware store wouldn't
take back a half bundle,of course, and I was wondering about using it
for boat flooring. after all, it's not going to rot, and the weight
doesn't seem to weigh much different than plywood. . and I've seen pics
of boat docks made from the same material.

Any reason why I shouldn't use it?

THANKS!
Tim