5 Unique Differences between Marine and other Plywood Grades

Are you embarking on a boat project, or frankly any project that will be outdoors or exposed to moisture and the elements. If so, you need to know the difference between the different types of plywood that is available.

In this episode, we share the specific differences between standard, exterior or Marine grade plywood. Despite what many may share with you, there is a difference. In this video, we will explain the differences and show examples so you too, can know what to choose and validate what others may tell you.

Join us on our journey as we continue to rebuild, refit and prepare our Formosa 51 Sailboat for our continued cruising journey. We have always loved the Formosa, bought one (on a bit of a whim) late in 2014, moved aboard this one right away and started to do our refit while living board. We are avid fans of Cruising Outpost and Good Ole Boat (Good Old Boat) magazines and love the ideas we get from them.

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Please watch: "How to repair a wooden mast, boom, spar or Bulkhead (Step by Step) "
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[LisaJohnsonArts]

This is such a helpful primer on this plywood. Thank you. I'm using some marine plywood to paint a floral painting onto for a client, and she is going to hang it outdoors ~ and we live in New England. So I wanted to learn more about this "canvas" before I started, and I appreciate your review. Happy sailing!

[KellyPerazzolo]

Thanks for the video. Greetings from New Zealand.

[gregbennett]

thank you for posting this video it will help me build my first scratch

[CheersWarren]

Hi Gil, not sure if somebody else mentioned in the comments but the only plywood I consider true ‘marine’ plywood is that built to British standard BS1088. But it should be a Quality brand too!
‘American’ marine grade ply is made from typically souther yellow pine.
BS1088 ply uses hardwood plys, Oakume is common. True mahogany for top quality stuff. The glue is water proof but also WBP, water and boil proof, which means it can be in boiling water for I think 30 minutes with out glue failure! Impressive!
Basically you can leave BS1088 outside almost indefinitely. We had an old fiberglass open boat with 3 pieces of 3/4” marine plywood as the floor, underside, frequently soaking wet. Never failed in 30 years the family had it ! The good stuff!
Cheers Warren

[julianklich]

Good job, just the comparison I needed to make the decision between plywood types.

[Hundert]

Thorough video, thanks for caring. Really makes me feel better about having my RV kitchen countertop made using marine plywood. Sailing is the BEST, Prost

[volkswatson]

Hey Gil, this is a great explanation. I’ve read so many different forums and opinions and they all seem different, but your vid explains well. Thanks!!

[michaeltillman]

I'm glad you did the video. That really clears up questions that I'm sure a lot of people have and saves us a lot of time doing research that will slow down a project. Your videos are getting really good. High quality work with good computer graphics. The little hand holding a pin was fun. 😎

[johngrajales]

This was detailed. I'm looking to make my own desk and was looking at differences. Was looking to go for the cheaper one but this just does it! :D

[Canadian_Eh_I]

Thanks I learned a coupel of things. I plan to use this for building speakers enclosures because of its superior strength

[EddieBoes]

August 2023 here. I was quoted $162.50 per sheet today of 4’x8’-3/4” thick (quantity of 8 sheets). This is in Northern Virginia.

[JB-dmnc]

Thanks Gil, great subject. Clears up a lot of questions. Make it a great day!!

[johnbolongo]

Great presentation. I own a boat and work in the building department of a home improvement store and learned a bunch. Thanks.

[dennis]

Hello and thank you for the video. I am a structural engineer and just had to add my two cents. We need to be a little careful with what's said in this video. Marine grade plywood is not always made from stronger more durable wood. One of the most expensive marine grade panels is made from Okoume. Okoume has significantly less stiffness, strength and rot resistance relative to Douglas Fir which is used in most exterior plywood. However, Okoume does have one third less density. Also, plywood with less plies (aka: layers) typically has greater strength and stiffness along the length of the panel and less across the width. Increasing the number of plies will reduce the stiffness and strength down the length of the panel in favor of increasing the stiffness and strength across the width. In other words, increasing the ply count balances out the strength and stiffness. Increasing the ply count also makes the panel more dimensionally stable. This being said, if you are only interested in stiffness and strength along the length of the panel, increasing the plies will typically not help.

[texasturkey]

Thank you for the video, very informative and just what I was looking for. However for my project I think I'll just go for exterior just because its really just for a small flat bottom paddle boat for putting around the lake in.

[ThompsonBMXbikes]

I didn't realize there was more to it than just pressure treated wood. Thank you for making my brain Fuller dude.

[mohdshahir]

Hai... brother thanks this information

[michaelbacile]

I built my skiff out of 1/4 birch underlayment (9$ sheet) it’s held up great for going on 7 years now

[Zorn]

I am doing a refit thanks for the video

[papermedmask]

great video. I just bought an old wooden boat. Your explanation helped me make an easy decision on what to use.