Marine plywood

Hi guys I'm new here and have a question. I just bought a Tracker tournament v-17 that needs the wood and carpet replaced. I understand you cannot use treated wood so do you use the marine plywood? Do you order online or try to order it from a local dealer? Thanks in advance. Shane

I personally would never spend the extra money on marine grade since even the marine grade should be waterproofed anyway. I use regular A/C plywood and then waterproof with thinned polyester resin (fiberglass resin), thinned with acetone.

What is A/C plywood? Or what does the A/C stand for? How thin do you make it? Thanks again Shane

The popular thing to do that alot of us do is to use regular plywood that has been coated with at least 3 coats of spar urethane. I used the Minwax brand 'Helmsman Spar Urethane" in a spray can. Put 3 good coats on being sure to hit the edges really good. Then one more coat one everything is assembled (if you can) or after making any additional cuts or holes. I then painted mine OD green.

The fiberglass resin mentioned by Levistephenson is very popular too. It seemes to me that it would be a better option because it totally encapsulates the wood allowing no moisture whatsoever to get enter. it is a little more costly (I think) and requires more work. The Spar urethane encapulates the wood too but not to the degree that the fiberglass resin does.

Then you have those that choose to use Thompson water seal or a similar type product. This is easy and very inexpensive. but it is not as good as the others (IMHO). I say this because if you have ever had a wood deck and used Thompsons you know that it is not a once and done application. It needs to be reapplied regularly.

If you are planning on building your rig and using it only for a year or so then the Thompsons may be an option for you. If you want to keep it for a few years do the Spar Urethane. If you plan on building this rig and keeping it for many years without altering the deck or changing anything go with the resin.

None of it is as good as using Aluminum though. strong, waaay lighter, and it will never rot. Just be sure to use hardware that will not corrode the aluminum.

welcome to Tin boats

the most popular thing that i have noticed is to use normal plywood and COVER it with spar urethane. menards , Lowes , home depot all should have both.

Marine grade plywood is great, but its sooo overpriced its not even funny. plus a lot of the guys on here have seen it reduced to sawdust on some old boats that have been rebuilt.

One thing on plywood thickness I learned on my build was....Anything thinner than 1/2 inch Ply will curl up on you when it gets wet, even with more than 3 coats of spar and a couple coats of paint. I used 11/32nds (3/8ths) on my middle floor and up front I used a little thicker 15/32nds (1/2 inch) to give some addes weight on the bow. The thinner stuff curled up on me a little. Go with the 15/32nds (1/2 inch) for your flooring.

You could go thicker with 19/32nds (5/8ths) if you wanted, but anything thicker than that is just too heavy in my opinion and not needed. If you put foam between the ribs it will support the floor and eliminate bowing or flexing.

https://www.homedepot.com/webapp/wcs/stores/servlet/ContentView?pn=Plywood&langId=-1&storeId=10051&catalogId=10053


A little light reading on Plywood and engineered wood.

I'm not really modifying the boat it came out factory with all the decking. The compartment lids are all aluminum and the floor and decks are 3/4" plywood. I bought the boat from a buddy that let it sit outside and go to heck. So I am just going to put it back the way it is. I assume carpet glue will stick to plywood coated in the spar urethane?

skeeter1804 said:

I'm not really modifying the boat it came out factory with all the decking. The compartment lids are all aluminum and the floor and decks are 3/4" plywood. I bought the boat from a buddy that let it sit outside and go to heck. So I am just going to put it back the way it is. I assume carpet glue will stick to plywood coated in the spar urethane?

Click to expand...

Yes it will stick!

to be fair to the good marine plywood brands, not all marine plywood are made equal. some are truly marine grade, others are just a tad better than exterior grade. ask experienced boatbuilders about the brand they use. and even then, high quality marine grade plywood needs to be saturated with a sealing agent. because only the glue that binds the wood panels is waterproof, the outer layer of wood is still vulnerable to rot.

so i guess the practical choice would be use "regular" plywood, then just waterproof it.

Thanks you guys have been a lot of help. It looks like a lot of work but I got the boat cheap. I will get some pictures of how ugly it is now and share with you.

I buy no means am a expert on this...but here goes. I grew up in a family lumber yard in the 70s. At that time there were both interior and exterior glue plywoods. Not to many years after that all was changed to exterior glue. The A/C C/D type grading on plywood grades each side, for example A/C plywood has one side that is A grade and one side C grade. If you were building cabinets A shows and C gets hidden on the back side. You can buy A/A plywood with two good sides.Most plywood we are familial with is fir or pine. Better grades might be birch, wanut etc. and cost goes up accordingly.Now MARINE plywood.All plywood made in the better grades is Xrayed when it exits the mill. Plywood that has no voids in any of the plys that make it up are graded marine. Its purpose is not for exposure but strength. A sheet of 1/4" marine can be used as decking. With no voids in the plys you wont step through it.As I recall only 1 sheet in thousands milled would end up marine.Use regular a/c fir plywood, seal it up and youll be fine. Hope this helps....River

"marine plywood" is the same as "cabinet grade" They have a very smooth finish to the outer piece of wood. I know personally that fiberglass will not stick to marine grade, unless you scuff it with 80 grit sandpaper. Marine ply means that it has no voids. You will never get a knot hole it marine ply. (hence the reason it is so expensive) But as for putting it in a boat, I would not waste my money. When I am putting plywood in a boat I use treated wood, BUT I cover it with fiberglass all the way around. This keeps anything in the wood from eating the aluminum, and it seals the wood and makes it last for a LONG time!