A while back I posted about some Russian Birch plywood I bought at Home Depot. It was 17mm with 13 plies. There was no indication that it was waterproof/resistant but I decided to give it a try anyway. I put it through a pretty rigorous home test - boiled it for an hour, stuck it in the freezer for two hours, ran it through a wash cycle in the dishwasher, froze it overnight, left it in boiling/hot water for 8 hours and all with no signs of delamination whatsoever.

After this, I took the test piece and dropped it in a cup of water and left it on the windowsill. That was over a month ago. I took the piece out a few days ago and still could not pry apart the laminations using a knife. I'm pretty convinced this stuff is waterproof.

It is finished both sides (not that this matters for SOF frames) and there's not a void to be found. It is pretty heavy/dense but I'll take that over something of questionable strength/durability.

A 17mm, 2x4 sheet cost just under 30.00 but it was enough to do all the frames for my Disko Bay - as modified by Dave Genrty. That's not too bad a price in the big scheme of things. I'm not sure what a 3/4" piece of marine would cost but I can't get it here without ordering a full sheet = a lot of money for the wood and probably even more for shipping!!

I can't vouch for all Russian Birch found at Home Depot but this stuff seems to be good choice for boat applications. The company's name on the wood is Cutler Lumber but they may just be the distributor.

Just in case anybody is wondering.

Sean