Will wet plywood shrink back to it's original size when dry?

[macd]

>To repeat: the expression 'marine ply' is meaningless in many parts of the world. It is not defined, except on the whim of the supplier.

I have been holding this off to see how any times macd will say that marine ply is meaningless. When I bought our steel boat the owner is a shipwright who can make anything in wood and specialises in teak decks. I had worked out the the space on the aft deck could take a box that I could put all our warps in, a petrol container and spare gas cylinder. I asked he was happy to do it and he said yes. SIT DOWN FOR THIS MACD.

He recommended Dutch marine ply and explained why. When I picked up the box it had a small curve in the bottom that matched the deck shape at the bottom of the box and to my surprise a nicely curved lid. If a shipwright says there is marine ply I believe him.

Not for the first time your powers of comprehension are wanting. I have not asserted that there is no such thing as marine play. I have written that there is no international standard defining marine play (although there is a British standard, not that it's always honoured), and that many plywoods sold as 'marine ply' would not meet the standard demanded, for instance, by the bloke who built your box. Not everyone is lucky enough to have his skills in assessing the quality of a laminate, nor excellence of its supplier. That's why standards are important: to inform and protect the rest of us.

Many correspondents on these pages will have had unhappy experiences with so-called marine ply. Someone such as the OP, who is in the West Indies, may also have difficulty in finding a plywood of true marine quality.

 

[PetiteFleur]

Many, many years ago, in my youth, myself and several friends built a 46' ORO Wharram catamaran and we used Marine Plywood to BS 1088 which was the standard at the time but I understand this standard is no longer applicable in this modern age. It was 5 ply with equal thicknesses of veneer. Robbins Timber supply 'marine plywood' which is expensive but does look good. I believe the Dutch manufacturer was Bruynzeel Plywood.

 

[macd]

That seems about right, PF. Equally I believe that such standards as do/did exist aren't especially demanding, and 'quality' plywoods such as you and KE have mentioned will way exceed them. (I've also bought from Robbins, although quite a while ago, and it was good stuff.) But the vagueness of 'marine plywood' leaves room for a lot of inferior stuff, too. Regular and informed users of ply will have a good idea of which is which, but otherwise 'marine play' can be a bit of a pig in a poke, perhaps the more so with the rise in remote selling.

 

[KellysEye]

> Dutch manufacturer Bruynzeel Plywood.

That's the only one to buy if you want to guarantee high quality.