TOPIC: The Use of Non-Marine Wood(Oak, Ash, Pine)

As a new member I have been reading with abject horror about the use of non-marine types of wood. "Wood rot" occurs when the moisture content reaches 30%. Mahogany and teak with their natural oils inhibit this. Additional coatings will embalm these to make them impervious. Virtually all plywood is made with water-resistant glue but the wood is is still soft non-marine.

Trying to find a 2x12x16 teak or mahogany lumber for new stringers might be a little hard and expensive . Im not sure you know this or not but the vast majority of fiberglass boat builders all the way from the 50's through 80's or 90's or when ever have been using non marine grade wood in their boats as general practice . There's no secrets there .

White oak is still easy to find and a very good wood to use for marine use....NOT Red oak. In fact red oak is porous

It depends on what your doing. Century used Douglas Fir for their stringers, White Oak for the bottom frames and transom frames. They used Mahogany for the upper frames, bottom, side planks and covering boards on the decks. They used Avondire for the blond colored wood in the bow and stern deck insets.

Bob

TallTexan,

Exactly So.

ImVho, though plywood suitably laminated (AND encapsulated w/epoxy) into structural components is as good as (IF not SUPERIOR to) most commercially available "natural wood" parts available at the typical lumber yard.

yours, satx

Expense has much to do with it I'm sure. I used treated plywood primered and painted on my MFG years ago. Perhaps if it sat in the water it would be a bad choice but it was only in the water when I used it. I was using for years that way (14-15) until I got rid of it last year in as good a shape as it's been for years. Carpet had been replaced a few times on the wood also. The seats in my Winner I been putting together are treated. It was the only way I could have afforded it to be honest.

when I pulled the transom out of my rocket (1958) which had a 1962 75 hp johnny hanging on it since 1962 . I got the boat from the original buyer . it was made out of plywood and the fiberglass was stuck to it so good I had to remove it in pieces. so if a transom that is 56 years old held up that good I think if I use polyester resin I think it will outlast my life. i'm in this hobby cuz I enjoy boats , now if I do not do what the big buckers do I guess I have no right to be in it. just my 2 cents, if that is enough. greg

Sorry I guess I got off on a bit of a tangent. When it comes to plywood it really depends on what you buy. IMHO using CPES is a must if you really want it to last. The other thing is too make sure your using a good VOID FREE ply, especially if it's going to be structural, transoms, deck etc. I think if I had to redo a deck on a budget I'd get the CPES and whatever ply I could afford with the money left. Coat it all in CPES, glass it in and prime then paint. Keep a cover over the boat and it will last though your grandkids lives.

Century used marine ply to bolster the stringers in all their boats that had V-8's in them. I did the same for mine, used marine ply Douglas Fir so now voids with CPES over all of it.

White Oak is the best for rot resistant hardwood by far. The majority of the wood boat building companies all used it. It has a very tight grain and naturally rot resistant as stated earlier. White Oak goes way back to the tall ships so......

Bob

bob, I take what ever you say as gospel , you did not offend me at all. greg

I'm cheap by the fact I have to be. So nobody get offended by my cost cutting ventures in the boat hobby. I love my boat as much as that real nice one you got. I finished the Winner and it looked great. Well I been using it and it has more scratches than I have hair. But it is mine and I done it myself.

Me thinks treated plywood works. Marine ply is manufactured with different glues and has no voids but is pretty much the same wood as regular plywood.
Depends on how long you live. If you're 20 yrs old and want to run your boat for 50 years go with marine plywood. If you're an old fart like me go with pressure treated and glass after CPES treatment then you can use it as a burial vault and it will still last 30 years before the worms catch up with you
As stated by Bob, white oak is excellent for frames and stringers but is HEAVY, mahogany is pricey. ash will last if treated, pine needs to breath, if it's encapsulated it will get punky.

Greg,
LOL thanks but there are much more smarter people than me on this site!

Bob

bob, there maybe, but they will not talk to me. lol

No one mentioned that it is the HEARTWOOD that is decay resistant in species such as white oak, northern white cedar, teak, mahoganies, western red cedar, redwood, etc.... The sapwood of those species is NOT decay resistant.

As mentioned, red oak is not decay resistant.

In the past few weeks I have ordered 50,000 Board Feet (five semi truck loads) 4/4 predominately heartwood white oak for marine use. We will still have to sort and rip out the sapwood before we can use it for making the glued laminated timber members for the USS Constitution "Old Ironsides"

Andreas

Good point Andreas, completely forgot about mentionging that! DOH!

Bob

Andreas, are they rebuilding her again?? Seems like every few years. When I was stationed at Boston we were tied up across the pier from her in the early '60's.
Interesting to watch those old girls getting refitted. Was in Conn a few years ago where they are rebuilding that whaler.
Cal

I am glad to see all of these responses as we all get to learn. Granted, cost does influence our collective efforts but personally what else would I spend my SS on LOL. Yes BIG mahogany planks are expensive but it sure looks good and lasts. Having cut my teeth on Mahogany Chris-Crafts, I prefer to make my boat bullet-proof enough so my grandkids can enjoy a Falls Flyer too. That means I need to get 100 years out of it. A sidelight: when I demo'ed my 1950 C-C Commander flybridge it was completely rotten from morning dew(fresh water) soaking the marine plywood. I took to splashing bay water on everything. From 12 years as a liveaboard, I embalm EVERY piece of wood with CPES and only use 3M 5200 caulking - boy does that bond. And sure beats bathtub caulking.

63 Sabre wrote:

Andreas, are they rebuilding her again?? Seems like every few years. When I was stationed at Boston we were tied up across the pier from her in the early '60's.
Interesting to watch those old girls getting refitted. Was in Conn a few years ago where they are rebuilding that whaler.
Cal

Yes, "Old Ironsides" is going into drydock next year. We shipped two truck loads of glued laminated white oak and some Douglas fir/larch for hull planking and deck planking in the past two months. Several additional truck loads will be shipped in January and February. Some of the hull planking was 14" sided x 6" molded x 45 ft. long.

It is an honor to be selected to manufacture repairs timbers for the old gal! We have been making glued laminated timber members for the historic ship since 1963.

Andreas

Wish I could see her. I'm sure she is getting the best there is. Thanks.

Very cool Andreas, good on ya!!!!!!!!!!!!!!!!!!! Love that old ship, it' been years since I've seen her. The USS Constellation is up in Baltimore Harbor, 2 hours north from me.

Bob

Observation. When sealing plywood you can only seal the outer layer of each side. That's approximately 1/16 to 1/8" of an inch of wood. then you can seal the edges and if you're lucky depending on what you're using and it's viscosity, you Might get up to 1" penetration. Sooo it's still all about ensuring that your overall care and maintenance program ensures that the overall encapsulation of the wood does not get penetrated. If it does it's imperative that the penetration is immediately coated with the proper sealant and not allowed to be exposed to the elements. If this is done then almost any wood with the strength to carry the load will do an adequate job. It's all about encapsulation of the core material. Mahogany rots too if it's not cared for. Any wood will. Some takes longer than others. Again My Opinion and it's worth every penny you paid!!!

I've been sitting on the sideline here soaking up all the info. Now I can tell first hand what worked for me when it came to preventing and stopping rot. Years ago when I lived near a large river one of my neighbors, an old experienced salty geezer had a wooden dock that just lasted forever, at least for the 20 years I lived by him. It was just pine logs pounded into the mud bottom and planked with pine boards. What he did every few years when the river was low is put a heavy soaking coat of ethylene glycol (anti freeze)on every exposed board. It kills rot spores and soaks in deep.
When I rebuilt my woodie Century in 2005 I soaked the new planking and white oak frame(s) with antifreeze before painting. I sold that boat last fall and it showed absolutely no signs of rot after 9 years, even around screw placement areas. In spring I would dump a gallon of antifreeze in the bilge and fill with water to soak it up and it still would show no signs of rot even when I picked around mating areas.
Here's an article from ACBS that's of interest about this.
www.acbs-bslol.com/gadgets/d97woodrot.htm
Just my .02

It's not the wood, it's what you do to it before, during, and after installation. You can use corrugated cardboard if you put enough layups of resin and glass on it.

I notice no one has mentioned OSB, and I realize it is usually looked upon with disdain in boat building... but I gotta tell ya, when you can buy a 4x8 sheet of it for $19 that's warrantied against delamination for 50 years and has no core voids. It makes you think...

I've lost count of the number of OSB floors I've replaced. They turn to pieces if they get and stay wet in a boating environment. Crusiers used it for floors in the 70's on their Ralley series. You get what you pay for. Good for new construction housing walls, bad for boat decking. IMHO.

63 Sabre wrote:

I've lost count of the number of OSB floors I've replaced. They turn to pieces if they get and stay wet in a boating environment. Crusiers used it for floors in the 70's on their Ralley series. You get what you pay for. Good for new construction housing walls, bad for boat decking. IMHO.

Like I already said, it doesn't matter what the wood is... what matters is what's done to it before, during, and after installation.

Take a sheet of OSB and epoxy coat it, install it properly, and apply a water shedding finish to it and it'll outlive you if the boat is properly taken care of.

Like Miss OSB:
www.bradfordmarineyachtsales.com/yacht-sales-65-hugh-saint-motor-yacht.shtml

Yeah, a $10M yacht made out of OSB plywood.

thompsonboat wrote:

In the past few weeks I have ordered 50,000 Board Feet (five semi truck loads) 4/4 predominately heartwood white oak for marine use. We will still have to sort and rip out the sapwood before we can use it for making the glued laminated timber members for the USS Constitution "Old Ironsides"

Andreas

Anreas, nice to see she is in good hands. I missed it when the Charles Morgan was docked next to the Constitution this summer.

Todd
(relative of Commodore Issac Hull)

thompsonboat wrote:

In the past few weeks I have ordered 50,000 Board Feet (five semi truck loads) 4/4 predominately heartwood white oak for marine use. We will still have to sort and rip out the sapwood before we can use it for making the glued laminated timber members for the USS Constitution "Old Ironsides"

Andreas

Anreas, nice to see she is in good hands. I missed it when the Charles Morgan was docked next to the Constitution this summer.

Todd
(relative of Commodore Issac Hull)

As a former owner of two Chris-Craft bull noses, "Miss OSB" prompts the question how does it look varnished? I don't have the will power to paint wood when there is varnish.

As a side note for wood preservation, Owners manuals for new Chris-Crafts suggested the use of rock salt in the bilges for of of their fresh water users. Pickling works.

Falls Man wrote:

As a former owner of two Chris-Craft bull noses, "Miss OSB" prompts the question how does it look varnished? I don't have the will power to paint wood when there is varnish.

You don't have to have the will power to paint or varnish when you own a 10 million dollar yacht, you pay people to have the will power to paint and varnish for you.

A little more clarification on the OSB:

Most OSBs are made with a phenol (epoxy) based resin, if you try to use a polyester resin on it, the results will be poor. Poly resin and phenol resins don't mix well... but you've already saved enough money on the plywood to afford the epoxy resin, so use it.

jigngrub,

WELCOME ABOARD.

yours, satx

the article said the buyer went boobs up hence the sale. He'd have to do the varnishing.
I grew up with Palmer Johnson in my back yard, (almost), so I know they do not use OSB.
Reality is that production line boat builders do not take the time or need the expense of properly preparing OSB for line production models. The Ralleys were glassed on top and bare underneath and that's what led to their failure. Just sayin'
Cal

63 Sabre wrote:

Reality is that production line boat builders do not take the time or need the expense of properly preparing OSB for line production models.

In reality, fiberglass boat manufacturers are moving away from wood and going with composite materials that don't rot, and have been for more than a decade. Aluminum boat manufacturers are going with either all aluminum builds or CCA pressure treated plywood to keep their boats from rotting. These are also options for the backyard boat builder/repairer, but that's not the topic of this thread.

I'll be doing 2 different OSB/epoxy builds (one aluminum and one f'glass) in the very near future. I'll be documenting them in the Members Projects forum, pop in and have a look if you care to.