Can't help you with marine ply. My Local plywood dealer only stock 1/4 inch fir ply -- read that heavy weight. I got my door skin from Home Depot. It has one dark side (luan) and an unknown lighter side. I choose to have the lighter side on the outside. I have to pick the whole stack to choose 4 sheets; one end up with an unnoticed void, about a foot from the bow end,which snap when I force the plywood to conform to the curved Guillemot bow. I just cut that out and strip built the bow. The stress on other boats may not be as extreme; therefor, it may not be an issue for you.
Good luck.

: Pete,
: Sounds good all around. Price is reasonable and 3mm is good for the deck. You
: may want to use glass in and out if you use the 3mm for the hull. In any
: event it is superior to 4 or 5.2mm lauan. I think the BS1088 standard is a
: British (read as Lloyds) marine ply standard adopted by the EU. It denotes
: a very high quality product. The EU is swarming with bureaucrats enforcing
: these standards, so I doubt anyone would attempt to export a substandard
: product. So as long as it doesn't have any signs of Chinese (People's
: Republic) origins you should be safe.
: Pete czerpak

: Peter C.,
: Speaking of local suppliers. I'm out here in the woods of Duanesburg. Where
: do you get your marine ply from? Know of any local supplier of 1/8"
: doorskins?
: Geo. C.