Marine Grade Plywood

I'm re-doing the floor on my boat. I've been pricing out marine grade plywood. The price of 1/2" is obviously much cheaper than 3/4". My question is, is 3/4" necessary?

It just depends on the specifics of what your doing. How large of an area are you flooring. Also what kind of material and how much bracing are you doing. If you have plenty of bracing and support you could definitely get away with 1/2". If you are going lighter with the bracing then you might want to consider 3/4". If you could give some more specifics regarding your project we could help a little more.

I plan on getting some AB Marine Grade Plywood from Menards. I have my boat framed with cedar 2x2's as pictured.

You don't have to use marine grade. You can use exterior grade plywood. Just don't use pressure treated plywood.

lckstckn2smknbrls said:

You don't have to use marine grade. You can use exterior grade plywood. Just don't use pressure treated plywood.

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This. I used exterior grade fir for my transom 2-1/2 years ago. Still looks brand new.

Good advice. Next question, 1/2" or 3/4"?

You look like you have a lot of bracing there. Personally I would go 1/2 inch.

1/2" is thick enough to support seat posts?

buckeyebrewer said:

1/2" is thick enough to support seat posts?

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I would locate the seat posts then cut a piece of the 1/2" plywood a bit bigger than the post mount and glue and screw it the the underside of the 1/2" deck before installing it.

gillhunter said:

buckeyebrewer said:

1/2" is thick enough to support seat posts?

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I would locate the seat posts then cut a piece of the 1/2" plywood a bit bigger than the post mount and glue and screw it the the underside of the 1/2" deck before installing it.

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Yep, gotta back it with something. I used HTPE cutting board.

1/2 in should be plenty with the support you have. Like others said just add some extra support around the seat posts and u will be good to go. Looks like it's going to be a mighty fine vessel