Marine Grade Plywood?
Marine grade is an absolute must. Jeff H, others right. The lack of voids is even more important than the adhesive. I have experience with (interior) bulkheads that were replaced with "normal" plywood. Not worth going into here, but the result in (admittedly humid) Hong Kong over a few years was unspeakable. Those bulkheads have now been replaced with what I hope to be a bullet-proof marine-grade sheathed in epoxy.