Plywood Shopping!

     Well, Spring is coming again soon, and it is time to get some marine plywood for the new boat. This will be the first of many investments into lumber. There are a ton of choices to be made. Previously, I just used exterior radiata pine, and it works fine on the small craft. It is easily repaired and touched up.

    With the Mystnyx houseboat project, it will require a higher grade of wood. The weight of the boat means it will be difficult to do any repairs. The cost of the project and the size makes it a prime candidate to use the best available materials. 

    That being said, its worth a look at the various wood types. Here is a good little primer that I wrote a long time ago about wood types: https://shadyislepirates.com/?q=node/39

    Woodenboat magazine also has a great write up on differences: http://woodenboat.com/marine-plywood

  Another great source of information on specific differences in Marine Plywood:  https://www.wolstenholme.com/pdf/Marine%20Plywood%20Comparison.pdf

   This is an interesting write up taken from the Glen-L forums: 

"The Baltic Birch plywood's are a sound choice if you can confirm that they are made with waterproof glues, more specifically the Phenolic Resin glues.
Also with the Baltic plywood's the grading standard is considerably different than what you see here in the (West). While we have (APA grades) A, B, C and D grades, plus Marine grades (Mar A-B indicating that it's Marine rated with one face being A grade and the other side being B graded) plus the British standards BS1088, BS6566 (although now only used for historical sake - the BS standards are no longer "certified" by Lloyds) they do not equate to what you may see with these birch plywood's.

 The Baltic grading system is typically the Russian GOST system. The plywood is made with two different types of glue. One is a phenolic glue, which is waterproof/boilproof - so what would be considered "marine rated" - it is identified on Baltic Birch with an "FSF" stamp. The second type of glue is melamine based, and while (technically) "waterproof", water "resistant" is more correct (on our side of the pond this would be classified as a sheet that can be used (structurally) if "protected" - like under shingles on a house roof etc. This second type of glue is identified with an "FK" stamp on the birch panels (and should be avoided on the hull/transom, but fine for interior stuff - bulkheads etc). 

Also the grading system is typically with a double letter (single letters exist, but are not often seen on commercial panels), so you will see BB/BB or BB/CC. Just like over here the grade has to do with the quality of veneer layers, how well they are joined to form a single layer (higher grades = closer joins = less gaps etc) but the GOST ratings are actually a little more stringent than on our side so a BB rated birch panel has considerably better joins than a B grade in the APA rating system.

So while a Mar A-B would be a preferred structural marine panel and would roughly equate to a BS1088 panel (using the lloyds rating), a BB/CC FSF Baltic panel would be pretty close to the other two graded panels.
There is one other advantage to the birch and one detractor.
The advantage is that for any given thickness it will contain more plies than an APA panel, and usually "at least" equal to the BS marine ply, and considerably more plies as the thickness of the panel increases.
A 12mm (roughly 1/2") panel with an APA rating of Mar A/B would have (typically) 5 plies. A BS1088 panel and the Vost panel would have 9 plies.
On the downside, the BB and lower rated panels allow "patches" in the face plies. These are seen as very small football (not soccer) shaped "plugs" in the face veneer. These can "pop out" under extreme stress/flex and should be avoided for major structural panels. In the APA system you generally only see the patches (albeit about 2 1/2 times the size of those seen on VOST rated panels) on C grade faces and they are usually identified with a grade of "C-Plugged". 

Now, for all my yapping here, this is my position on using Baltic Birch.
Given the "crap" that the APA rated stuff has turned into in the past 20 years, I consider the B.Birch "far superior" to anything on the market with an APA rating.
In the last 15 or so years even the (formerly) BS rated stuff has gone way down hill. So unless you are chucking big bucks for Joubert certified BS1088, the stuff that's being passed of as 1088 is barely better than 6566 Aquatek, so hardly worth the premium.
Because of that, if you can find some BB rated Baltic Birch with the waterproof glue, FSF, stamp, you will have a vastly superior panel both aesthetically and structurally to anything else on the market. The biggest issue in North America is sourcing full sized panels. It is typically imported here in 5'x5' panels only."

In the end, I order a ordered a pile of yummy specialty plywood from Smith's Plywood for the new boat build.. U can spend quite a bit of time in a plywood specialty shop...  I got the 1/2" in Baltic Birch, and had it delivered.

Alot of nice grains and beautiful wood. Smith's doesn't have Meranti or Okoume.  I then went to PJ White's and was able to get both BS-6566 and BS-1088 Meranti for the build. I now am all set. Very excited to get going!