Flatboat transom replacement

[slip knot]

My 14ft flatboat (cirhosis of the river) transom is shot. I replaced it about 10 yrs ago with pressure treated plywood. This new pt plywood is all treated with chemicals (ACQ) that are not compatible with aluminum. Hate to spend the $$$ for marine grade ply but may have to cough it up.

From what I understand the ACQ treatment is for insect repellant anyway has anyone used plain ply in this application before? I've used some of the newer generation OSB with epoxy on some remodel work for subfloor that would probably work but it weighs a ton.

Anyone using anything different?

Thanks guys...SK

[Ray]

Starboard. Will never rot. But I am not sure if it is good for an engine to hang off of.
They make it in all kinds of thickness's.

[coachlaw]

Man, you simply cannot beat good old marine plywood for this application. It's expensive, but you'll only have to do it once. My dad built a club house in the back yard for me when I was 7 years old. He put marine plywood on the roof. I'm 36 and the old club house is all messed up, but that roof is just fine. 29 years bare in the elements, even through Katrina and I'd take that roof off and use it for a transom today.