Technical Plywood Core question

[saurav16]

Hi,

Another quick question: If you are looking at a boat and the stanchions are loose and rusty water can be felt inside the cabin from the washers and nuts holding the stanchion on the underside, is it a good bet that the wood core along the deck has rotted out (its marine plywood)?

[Gary M]

A moisture meter is your best tool to determine water penetration and should be your first step.
Tapping with a plastic hammer or the handle of a screwdriver will give you some indication of mushy coring, but unless you are experienced at this you need a surveyor to look at it.

A leak here on it's own is not a great sign but is not conclusive.

Gary

[hellosailor]

I'm a pessimist. I'd say yes, given that most bolts aren't properly sealed around where they penetrate a deck, the deck may be damaged. The only way to tell is to unbolt stanchions and examine the deck under them. "Proper" design would be solid fiberglass in those areas, not just cored decking, to avoid this problem.

Loose stanchions and rusty water inside, also means the previous owner wasn't taking care of business and you need to check for other neglect.

[sailingdog]

Yup... the marine ply has probably started to rot...but you also have to check for water migrating along the core—since water can migrate along the fibers of the plies in the plywood... and go a long distance from where the water entered.

[Sailormann]

There might not be any core that close to the edge of the deck. Look at the underside of the deck. If it is all the same level then it is (probably) either all cored or all solid. If there is a difference in levels, then the core ends where the thicker part ends...