Marine plywood for deck

[hyboats]

want to laminate deck with marine plywood, I know it's not good but lower cost (small pics wood, about 3'' *3'')
1 Should I make the plywood saturated with resin before use it.
2 In bolt (for seats,handrail, cleats) places I want to use GRP plates instead of plywood, is that good ?

[tunnels]

Originally Posted by hyboats

want to laminate deck with marine plywood, I know it's not good but lower cost (small pics wood, about 3'' *3'')
1 Should I make the plywood saturated with resin before use it.
2 In bolt (for seats,handrail, cleats) places I want to use GRP plates instead of plywood, is that good ?

For places where things get mounted theres a few ways of making it strong ,Ply is the usual method but make sure you use good glass under the plywood pad ,First a woven 250mm square and csm ,then another 150 square and csm set at a 45 degree angle to the first one so the load of pull is distribted over a big area , Then csm and one woven and another csm over the ply .

In places where its impossible to screw nuts and reach with you hands i use 8 mm thick aluminium plate and glass the same ,then you are able to drill and tap a thread into the plate and bolt on you cleats etc etc .
Wood goes rotten over time .
Most important is to make the pads big to spread the load over a big area . Under the nuts use big flat washes and spring washers as well ! nothing worse then nuts that keep coming loose even if they have nylock huts

[alan white]

Tunnels has some good info. Usually, we find problems in glass/balsa core decks where little was done besides to seal bolt holes at the surface---- totally inadaquate but done frequently in the early days of sandwich construction.
In your case, where you have a solid plywood deck, I'd suggest you drill your holes oversize, seal the bottom with something (poly-covered pad held tightly with a prop, etc.), fill with neat epoxy, and then redrill smaller holes.
This is a very sound practice. It is easy and it won't rot.
For big loads like bitts or rigging mounts, add another layer of plywood under the deck beforehand and obviously you want to spread the load by making the pad large enough.
It works well to bevel the edges of the pad undersides at 45 degrees for aethetics and ease of finishing. Also set the pads in an epoxy/filler mush to make sure there're no gaps between and to make a monolithic structure.