Plywood for Transoms, Decks, and Stringers

[Woodonglass]

This came up on a thread the other day so I got to Surfin and found some information that I wanted to pass along.

Baltic Birch Plywood IS some very good stuff. It's an excellent candidate for your boat building needs and I HIGHLY recommend you consider it for all your wood needs. It IS a bit pricey and Not easy to find in 4x8 sheets (Typically sold 4x6 or 4x5) I did find out that Menards carries the 3/4" 4x8 sheets for less than $80 bucks a sheet. If you're lucky enough to have a Menards in your area and want to have some of the best plywood you can get your hands on then THIS IS THE STUFF TO BUY!!!! It is NOT the typical Birch plywood most of us are accustomed to seeing in the Big Box stores. It IS totally suitable for the marine environment. NO VOIDS and Mulitiple plies (13) of quality Russian Birch wood. Do some research and you'll soon see that this is some quality material. Don't know why I didn't think of this before now.:facepalm: $700 bucks should do most transoms, decks and stringers for boats 20' or less. Maybe less. That's just about 40% more than the Ext. Grade plywood costs but it IS SOOOOO much better grade of material. For the Transom I KNOW it's worth it. You'll have to decide about the rest. Just passing on what my research and experience turned up. I've use BB plywood in my woodworking for years. 4x5 foot panels in 1/2" thickness Very stable stuff. I really never realized it was exterior/marine grade.

http://www.menards.com/main/building...-external-mcom

 

[Scott Danforth]

thanks for posting WOG. and yes, I miss Menards. they also carry arauco plywood

 

[Ned L]

May I suggest reviewing this too.

http://forum.woodenboat.com/archive/index.php/t-68001.html

I won't disagree that it may be made with waterproof glue, but it is still birch. I'll still stay away from birch.

 

[jbcurt00]

May I suggest reviewing this too.

http://forum.woodenboat.com/archive/index.php/t-68001.html

I won't disagree that it may be made with waterproof glue, but it is still birch. I'll still stay away from birch.

DozerII has used a GREAT Baltic Birch on several Starcraft builds w great success and to date no problems reported. He seals it w spar. He's in Canada, gets it there aomewherd, and whoever the maker/supplier, it wasnt available in the US when I looked them up for a US distributer.

As w many things, I regularly tell people to do some research for themselves and decide what suggested materials and products will fit their skill set, budget, purpose and most importantly availability

 

[Watermann]

Sounds great, wish I had a supplier in my area. I have to order marine grade from the a local lumber yard with 3/4" being 7 ply doug fir at $70 a 4x8 sheet. I bet that baltic is nice to work with, quality stuff always is.

 

[Ned L]

I can only suggest people look into the rot resistance of birch. There is a reason it is not used in boats.

 

[DeepBlue2010]

The reason for recommending alternatives to Marine grade ply - the correct material for a boat building job to begin with - such as Arauco ply and the like, was cost. Now if the cost is increasing by 40%, isn't better to just bite the bullet and use the right material for the job?


Aside from the notorious water resistance glue and voids arguments, try to cut a 1 foot * 1 foot from Baltic Birch and Marine ply and weight them both. Baltic Birch is significantly heavier , sometimes by more than 15% depends on the makers of both sheets.


Heavy boat consumes more gas for the same speed compared to a lighter weight boat (everything else held equal)
So, is there any real cost savings or it is just false economy?

 

[Ned L]

I agree this is to help identify more cost effective alternatives to "marine plywood". There are better alternatives to "marine plywood" than birch. Regular ACX or BCX is less expensive and much better in rot resistance.
.... I certainly can relate to this issue, I used a couple of sheets of 3/4 Okume plywood in my current rebuild ($175 a sheet).

 

[bonz_d]

I'll take this thought one step farther. Wood type vs. wood sealing.

If sealing the wood is all important in any build which I think we all agree upon then I have this question and thought. If encapsulating wood in an epoxy shell then what difference does it make what type of wood or glues are used to make the panel? After all epoxy is supposed to be the do-all end-all of sealing solutions. Once properly done any wood should be impervious to any water intrusion. So why couldn't interior plywood be used if it is encapsulated in epoxy?

 

[Woodonglass]

These discussions are always a hoot!!! Soooo many different opinions from soooo many directions. When I was a kid, working in a Marina, we rebuild an old 15 yr. old runabout and when we tore out the old rotted deck and got down to the half round stringers and tore into them we found they were glass encased cardboard. Yep the cardboard was still there. Albeit it was waterlogged but still there. As stated IF the resin and glass is done properly and the care and maintenance is done well then it really doesn't matter what wood is used. I DO agree about the weight soooo, that should be taken into consideration but, I also think the voids and the strength of the structure is important as well. I think this plywood would be GREAT for transoms and stringers but for decks, it prolly isn't as important. It has been used in boat building quite often and is still used. Lots of Pro's and Cons for all the reasons already stated. Just putting it out there for everyone's consideration and ability to choose. I think for a "Tinner Transom" encased in Epoxy and then Painted it would make a very Strong and Long lasting transom especially if it was sealed with the Old Timers Recipe!!!! :happy:

 

[DeepBlue2010]

Design is a balancing act. And as long as the re-builders are making informed decisions and are aware of the pros & cons of different selections, the final decision is a personal preference & responsibility. The debate is defiantly worth it and it is a healthy debate. Thanks for giving us something to think about Wood, it is getting really systematic (a.k.a boring) these days at work

 

[bonz_d]

I swore to myself that after the last time, a couple years ago, that I would not be drawn into this debate again because there is just no winning this and will state once again that in my own opinion there is no right or wrong way just better ways. At that time I did spend a lot of time and effort to research this topic from many different angles. The one conclusion that was constant is that water and plywood do not play well together. There is no 'perfect" solution.

As stated there are a lot of elements that come into play when building or rebuilding. Available materials, costs, skill level, finish level, use and even cosmetics. Even beginning construction plays a part. Aluminum hulls are much different than glass hulls, both require a bit different approach and requirements. Same can be said between large boats and small boats.

I am a small boat user and that's were my interests lay and that is what I watch for and study. Then it is mostly tin boats because for me they are easier and less expensive to work on therefore I tend to stay out of the discussions in regards to glass boats. I just don't have the experience or interest with glass boats and resins that many here have.

My personal opinion is that one can build a very nice safe, functional boat that costs little and will still last or one can build a monument that cost tons of money and is very beautiful. It still comes down to what the owner/builder can afford or desires. Neither way is right or wrong. Which is why I try not to criticize others work on this forum.

Lastly I will state that that I try not to be critical of those that try new products or techniques just because that's not the way it should be done. How do we know unless someone tries it? For example the Rustoleum DTM latex paint that I'm experimenting with in my build.

WOG, you and this forum have turned me to the "Old Timers Recipe" and for what I am doing it fills the bill very well. This forum has even made me aware and to be selective while I'm rummaging thru the stacks of plywood at the stores.

Enough of my perspective, enjoy the discussion and happy building to all.

 

[DeepBlue2010]

I'll take this thought one step farther. Wood type vs. wood sealing.

If sealing the wood is all important in any build which I think we all agree upon then I have this question and thought. If encapsulating wood in an epoxy shell then what difference does it make what type of wood or glues are used to make the panel? After all epoxy is supposed to be the do-all end-all of sealing solutions. Once properly done any wood should be impervious to any water intrusion. So why couldn't interior plywood be used if it is encapsulated in epoxy?

[FONT=&quot]Because moisture will migrate regardless. Water will find its way in if not through microscopic cracks in the laminate it will be through condensation. From a design stand point, it is better to have multiple defense lines than relying completely on single one. This makes your single point of failure catastrophic if it compromised.JMHO[/FONT]

 

[Woodonglass]

I DON'T like it when these debates get "Heated". I only offer up my research observations to allow the members here the benefit of it. As I usually state, "It's your boat and you're free to do with it as you see fit!" I really mean that! I also mean it when I say I'm a C.O.B. and I usually pursue the least expensive method when trying to solve a problem. I try to be innovative and experimental when approaching a problem. I am also very attentive to safety and structural soundness. Putting all these factors into perspective I still think it's beneficial to post all the different opinions

 

[61mysteryboat]

I'm the guy who initially posted this topic on another thread. Didn't know it would create such a firestorm. WOW. Great to read every bodies passionate responses. I brought it up knowing from experience that quality baltic birch is super strong, stable, and uses exterior glue. My only experience however is through extensive woodworking. I have no boat building experience, yet. Starting first restoration. I just figured, " what difference does it make if it is totally encapsulated ". I don't understand how condensation could make a difference in a sealed area. The only moisture in there would be what was inside at the time of encapsulation. Can epoxy allow moisture to permeate through? Group hug ?

 

[Woodonglass]

Yeah, I'm not sure about the condensation in a totally encapsulated resin coated wood laminate. Not sure how that's possible when the wood has been precoated and saturated with resin prior to the glass being applied especially with epoxy and it's qualities. I really think experience and research tells us that it would take a LOT of years for this to occur unless the outer barrier was breached in some way and then as stated by others, the type of wood used, becomes moot, other than the length of time it would take before total failure would occur. ALL wood eventually rots when exposed to water over an extended period of time. Properly encapsulated wood won't/can't. My transom is 55 years old and no evidence of condensation or rot anywhere and it's polyester encapsulated. I think that's pretty good evidence that it's all about proper care and maintenance along with good glassing techniques. Not saying that the use of good quality wood with good water resistant qualities isn't a good idea, cuz it is, but...oh well I think everyone gets the idea!!!

 

[bonz_d]

Seems that we are all learning in time. I will still stick to my POV that at this point there is no "perfect" solution, though there are many solutions. Some are just better than others.

If one has the materials readily available and cost is not an issue then by all means buy the best that are available and the results should be fantastic. Which then leaves the question to what is best. I have found what is only best for me which is all any of us can do.. I also just enjoy watching the pride that people take in their work even if they are not building monuments.

I really do enjoy hearing of alternative methods or ideas. I've even incorporated a few into things I've been doing. After-all this forum is also supposed to be an exchange of ideas isn't it? Which reminds me, I need to update my own thread.

 

[DeepBlue2010]

Heated debate?! Firestorm?! Seriously guys?!!!!


The thought that was offered and I responded to was "if the wood will be encapsulated, what difference does it make which wood to use" my point was this assumes that the laminate will never be compromised. I don't like to make these assumptions. It is my nature not to make optimistic assumptions like these, if anyone is comfortable making them, be my very welcomed guest. Personally, I have to account for the situation when this laminate gets compromised due to anything. Tighting the transom assembly can crack the laminate even before the boat gets in the water, hitting the dock in a rough day, leaky transducer mounting screw.
The difference between a novice designer and an experienced one ? at least in my industry ? is that the former assumes that everything will work according to the plan but the latter assumes that nothing will.

One more thing, I did not see this as a heated debate neither I tried to make it one. Someone posted a simple question and I responded with what I think is right. The thread is not remotely close to be a firestorm either. It is/was ? from my point of view ? a healthy debate regarding material selection with an opportunity for people to think through it. It is how we learn and discover.

 

[bonz_d]

I should probably just leave this alone and not be drawn into this but!

WOG 1st of all thank you for this thread and some insight to another product. Not being a woodworker I was unaware of Baltic Birch properties or use in a marine environment. Next, from past experience I think both you and I know this has yet to get to a "Heated debate" level as it has in previous posts.. I hope it doesn't come to that either.

In this case the reason I asked the question the way I did was two fold. One was because of the idea of using this plywood as opposed to marine ply or ordinary exterior ply. Which then always leads to sealing plywood methods.

My observation has been that the general contention, method, is to encase the plywood in epoxy. To which some feel is the only way to correctly seal plywood. That somehow this method makes it impervious to water, which if that is truly the case why would one have to worry about what type of wood or glue is used because it will never get wet.

Yet history and the number of glass boats needing repair that comes thru these forums proves this is not the case. Encased wood fails all the time. Also the research that I had done in the past also bears this out. It's just a fact that plywood that is left constantly exposed to water and allowed to absorb water will eventually fail.

So, is using marine ply encapsulated in epoxy the best method? I would agree that yes it is and offers the longest life under the same conditions as when the other methods are used.. Can this still fail? Yes it can and it does as seen here on this forum many times.

Wouldn't it be nice if we could all use mahogany marine plywood in out boats?

 

[Woodonglass]

When I used the word "Heated" I didn't Mean this one Had become heated. I was referencing Bonz-d's previous post about his reluctance to be drawn into these debates because they often to come to that point. Sorry for the bad wording. I DON'T want this one to get there either. As I said just wanted to ensure everyone knew what Baltic Birch Plywood was and how it could be utilized in the Marine environment. Everyone as made excellent points on ALL counts. I'll say it again, It's all about Good Glassin' Techniques and Good Care and Maintenance!!! Thanks to everyone for their GREAT INPUT!!!! Sorry for this OLD DUMB OKIES POOR CHOICE OF WORDS!!:facepalm:

I believe I was one of the first to bring the Arauco brand of plywood to the attention of the forum. It has 7 plies, very few voids and uses ext grade waterproof glue. It's wood veneers are NOT the best woods for marine use but again the price is right, it's structurally very sound and once encapsulated should stand the test very well. It caused some commotion at the time as well as my introduction of MDO plywood. I guess that anytime anyone introduces change into the equation, we should expect there to be some noise. I'm just to DUMB to keep my mouth shut!!!!