[Public-list] Re: grades of plywood

[Gordon White]

      I am not an expert in plywood, but I do know that the grades and 
expected use of the material are related to the glue used - exterior 
grade has to withstand moisture better than interior grade and I believe 
marine grade has fewer "repairs" or places where imperfections such as 
knotholes have been cut out and oval patches inserted, with the line 
going from "interior" construction grade to  furniture grade, 
"exterior", marine and finally "aircraft" grade.  Different woods are of 
course used for different  purposes. There are even more grades of 
plywood than of stainless steel, and like stainless, have different 
properties for different uses. The stuff used in containers doesn't have 
to look good and is probably a lot rougher than what you would want for 
Alberg coamings, and it is probably somewhat thicker.

    FYI, the coamings on Brigadoon II, built in 1967, are just fine. No 
cracks.

- Gordon White