: I don't think that there is a difference in size between marine
: grade ply and normal ply. The difference is in the quality of
: construction.

While I don't think it will make a difference it might be worth checking. V/C Cabinet Grade plywood, MDF, and Melamine 4x8 sheets measure out at 49x97, and construction grade is actually 48x96 spot-on. This is just because you can't use a messed up edge for cabinetry, not to increase the yield on materials. After sending $120 on a sheet of 3/4" A/A VC Cherry plywood you'd be ticked if you couldn't saw off yucky edges.

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