I was able to use door skin plywood to reasonable effect on boats about 10 years ago but it became useless after that. It seems plywood in the thinner grads suitable for boatbuilding have fallen in quality although I find the thicker stuff 1/2 or more is often better. Even marine plywood cannot be trusted, I used 6mm BS1088 ply for the bottom of a sailboat, I was unable to complete the finish for a year because of ill health and by the time I recovered it had started to delaminate. It used to be than BS1088 could be left outside entirely unfinished for years without that happening. Not only do you need to use marine ply, but it should either be Lloyds certified or a top brand like Joubert. This is only recent: I still have a short stack of 4mm marine ply which is good stoff from about 10 years ago.

The only non-marine ply that I would trust would be Baltic Birch but its awfully heavy and comes in weird (5 x 5) sizes.