Pressure Treated Plywood???????

What's better?

Marine grade or pressure treated plywood.

I have bought an older 18' Starcraft aluminum bowrider and the floor is spongy and needs replacement.

My plans are also to rebuild the transom.

BTW, it currently has an outboard and it will stay this way.

Thanks.

Mac

 

Check the WIKI

Take a look at:
http://www.boatdesign.net/wiki/MaterialsForBoatbuilding#Preservative-Treated_wood
where this has been discussed some.

I used well-dried 3/4" PT Plywood in replacing my transom 5 years ago, and it bonded well with West Epoxy.

 

But but but PT plywood will corrode aluminum like meth does brains. If you can isolate it from the boat with innertube rubber or something, that might work. You still have to be carefull about what fastenings you use.

 

UhOh

Thanks, Sam.. I didn't notice the aluminum issue.

If the PT is well dried, AND has a couple of coats of epoxy wouldn't it be pretty inert??

Anyone done this on an aluminum boat??

 

PT ply is not the same as it used to be. The safer chemicals (replacing arsenic, etc., have made the more recent PT more corrosive to less noble metals. I believe the problem is due to copper content. For example, building a deck onto your house in the old days, you would use galvanized nails, but now only stainless or ceramic coated screws are used. the zinc coating on galvanized nails will be eaten away in no time flat.
If encapsulated, use copper (not aluminum) drain tubes and do careful work. Transom pads should be something like stainless. In the end, care taken will pay off in keeping moisture out anyway.

Alan