In many years around the boating industry I have never herd of naval plywood .Are you thinking of marine plywood? marine plywood differs (Generaly Fir) from exterior in only a few respects.
! both faces are clear fir.
2 there are no voids of any kind on the inner plys.
3 It is much more expencive.
Both exterior and marine pllywood use the same glue.
If eather is not sealed from moisture especially around the edges each willill rot out at the same rate.
my quarrel with airstream is that they were too cheep to use any rotproffing be it preserive or epoxy saturation or other sealer to prevent the rotting of the floors
Jim Smith
1965 tradewind(the Silver Abaltross)
1992 Dodge Cummins Diesel