what ply for the floor?

[Scylla]

Ripped out the old plywood covering the floor of my 77 Rivi but neglected to check what size it was. Am thinking something like 6 or 8 mm, what do you think?

Damian

[MeyerII]

I don't know what the OG ply was on Rivieras, but when I redid my old one, I went with 1/2" marine grade plywood (about 13mm). I strongly prefer marine grade ply, as it will stand up better over time.