Keel Timber To Dry ?

[emichaels]

OK. I found a timber for my keel, 5-1/2" molded, 16" sided, 23' long.
It was logged and milled for the USS Constituition refit back in the early 90's. It is crack free. It was on the bottom of a pile of timbers, out of the sun and mostly out of the rain for a long long time. It is consistently 19-20 % MC.

So the question is, using metal floors and fixing the frames in steel, so to speak. Will the garboards open up and crack when this timber takes up water when the boat is launched ?

Should I try and rehydrate the timber by soaking it for 6 months or so.

What would be a good approach to using this timber.

I remember Bob S. once remarked "pick your poison" I think this is kind of one of those situations. I know the timber is virtually flawless, flat, straight, etc. So I know it won;t twist and crack while I take the next 3 years or so to build this boat. But as I questioned above, is there a potential problem lying in wait for me after launching ?

Eric

[Mrleft8]

Maybe yes...Maybe no. One thing to consider (And I'd wait for the "real" experts to chime in b-4 you do this....) is soaking it down with PEG100. In theory the PEG100 would displace any moisture, and subsequently KEEP all moisture out. ("all" being a subjective term, I'd imagine right about where you're at is where it would stay) The PEG100 would also keep the timber stable. I'll be interested in what the more seasoned, knowledgable guys have to say...

[Bruce Hooke]

PEG1000 would be rather expensive. I also thought it was water soluable and so would not stick around once the wood was in the water...

[Bob Smalser]

I don't suspect they've dried much yet in boats pulled in late October.

Head for a local boat yard with moisture meter in hand and measure the keels of a few to see. Carry a tube of 5200 to patch the pin holes you make.

[emichaels]

I don't suspect they've dried much yet in boats pulled in late October.

Head for a local boat yard with moisture meter in hand and measure the keels of a few to see. Carry a tube of 5200 to patch the pin holes you make.

I don't understand what you are trying to say here Bob.

This is a new keel timber for a new build. My concern is the .75-1" the timber might swell after launching.


Eric

[Bob Smalser]

I don't understand what you are trying to say here Bob.

This is a new keel timber for a new build. My concern is the .75-1" the timber might swell after launching.


Eric

What you want to know is the end state moisture content after you launch the boat. Knowing that, the amount of swelling or shrinking can be predicted after you monitor the timber's moisture content during the build and use that as a base line.

I'd do it for you just to know myself, but there aren't many oak keels around here. Doug Fir remains much drier than oak.

A 20-25% end state sounds right to me, but I'm guessing. Dr Jagels said once oak can get to 30%, but I'm not sure how many wet keels he's measured either. Either way you'll want to protect it with wet sawdust during the build.

[emichaels]

Ahhhhhhhhhh.....Now I get it Bob. I can be slow sometimes, tunnel vision. I was wondering if, before I paint the boat, that I treat the outside of the keel with copious amounts of cpes and epoxy to try and seal out the water to the point that it will take a longer time to soak back up. Thus making the transition slower and giving the garboards a gentle time of it adjusting.


My other thought is to cast my frame/keel floors in two pieces so each side will be able to move independent of the other side and thus not straining any of the bolts, oak or frames.

[Bob Smalser]

I was wondering if, before I paint the boat, that I treat the outside of the keel with copious amounts of cpes and epoxy to try and seal out the water to the point that it will take a longer time to soak back up. Thus making the transition slower and giving the garboards a gentle time of it adjusting.


My other thought is to cast my frame/keel floors in two pieces so each side will be able to move independent of the other side and thus not straining any of the bolts, oak or frames.

My guess is that you're not gonna have a problem at all providing you build on gravel in a tent and keep things damp. But what you really need is local experience with your wood and climate, not mine.

I'd paint the timber ends immediately with melted parafin wax for starters. I doubt the epoxy idea will work, or messing around with the framing desirable or necessary.

[emichaels]

Well this timber has been air drying for the better part of 15 years so kept outside it probably won't dry anymore. I will be building in a metal building on gravel and could easily soak the timber down each day while working on the framing, ect. But at some point I will need to pin the frames in place with the metal floors and that will seal the fate of the garboard seams.

[sawcutmill]

If has been drying for 15 Years, then you need to start building your boat, MC at this point in time, i dont believe, is of much consequence.Seal the ends like Bob said, and if you feel like Cpes ing, then by all means, i have found it is a awesome sealer! I have been using it on many applications ( have used over 10 gallons of it since the early 90's) and have had very good results.
Your boat will come to terms with itself when you build it, in other words, she come an go as it needs to, and therefore, so will you! It is a boat however, and it wants to be wet, build it, put in the water, and enjoy it!
BTW~ Use only ONE piece floors.Structurally better.stephen

[Bruce Hooke]

It seems like you could get quite a bit of movement in a 16" wide keel between winter and summer even once the boat is launched (assuming it is hauled in the winter). I wonder if and how the design accounts for this possibility?

By the way, when you measured the current moisture content of the timber did you actually use a method that would let you get into the center and measure the moisture content there?

[Bob Cleek]

Keep in mind that the way the grain runs will dictate the movement of the wood. If it is 16" sided, and that's on the quarter, it isn't going to move much relative to the garboard seam. If, on the other hand, the grain is running the other way, it might. The movement isn't going to be huge, though. Just build her tight and she should be fine. They've been doing it for years without a bit of problem. I don't thing you'd be the first to have difficulties with it. Thank your stars you found such a nice hunk of wood!

As for floors, you mentioned metal and steel in the same breath. I hope you were joking. DON"T use steel floors. Even if they are hot dipped galvanized. You just end up with all sorts of rust in the bilge eventually, not to mention problems with dissimilar metals in the keel bolts if you are using a lead ballast keel. (You didn't think I'd let you off so easy, did you?)

[emichaels]

It seems like you could get quite a bit of movement in a 16" wide keel between winter and summer even once the boat is launched (assuming it is hauled in the winter). I wonder if and how the design accounts for this possibility?

By the way, when you measured the current moisture content of the timber did you actually use a method that would let you get into the center and measure the moisture content there?

Well in regards to measuring into the center of the timber. The timber was 34' long. I cut it at 23' for the keel and will use the remaining 11' at the stem. I could then measure in the center of the timber and it was 19%. All the surfaces down to a depth of 2" (this is currently a 7-1/2" thick flitch ) , and the limit of the moisture meter, on both sides yields readings of 19-20%. So I am quite convinced it is consistently 19-20 % mc throughout. After all it has been air drying for a decade and a half.

[emichaels]

Keep in mind that the way the grain runs will dictate the movement of the wood. If it is 16" sided, and that's on the quarter, it isn't going to move much relative to the garboard seam. If, on the other hand, the grain is running the other way, it might. The movement isn't going to be huge, though. Just build her tight and she should be fine. They've been doing it for years without a bit of problem. I don't thing you'd be the first to have difficulties with it. Thank your stars you found such a nice hunk of wood!

As for floors, you mentioned metal and steel in the same breath. I hope you were joking. DON"T use steel floors. Even if they are hot dipped galvanized. You just end up with all sorts of rust in the bilge eventually, not to mention problems with dissimilar metals in the keel bolts if you are using a lead ballast keel. (You didn't think I'd let you off so easy, did you?)

Well as far as the grain runs, this is a flitch, completely off heart. the small side, ie. outter side of the tree, will be faced down. So the top of keel will be from the "center side" of the tree. This is how Bud McIntosh describes ring orientation in his book.

Any thoughts on this ????????

The floors will be cast manganese bronze. All fasterners are bronze and the ballast is lead. This is a problem with typing faster than I think. And both can be slow ! But one has to be slower....

Eric

[StevenBauer]

This is for the Hess boat, right? Or have you switched to the Herreschoff?

Look for an invite to our Caroling party on the 23rd. :)

Steven

[Mrleft8]

Is PEG 1000 water soluable? I suppose it must be, but as far as I know once it displaces the moisture in a timber, the timber does not "rehydrate". I may be completely off on this...
Expensive? Define "expensive" when talking about the budget for a boat with a 23' keel. ;)

[Don Kurylko]

Don’t worry about it Eric. There is no way to anticipate what the wood will do when it gets wet. But then, that’s what caulking is for – to absorb the stresses in the hull when the wood takes up. Undoubtedly you will need to re-fair the seams within a year or two because they will, as likely as not, spit out a lot of putty. Sealing the keel timber is a good idea too. Just make sure that the sealant will be compatible with any future coatings and compounds you may want to use. I think old timers used to apply liberal amounts of a mixture of Turps, linseed oil, pine tar and some other mystery ingredients to keep the big timbers from drying out too much during construction. Some swear by anti-freeze as a good sealer and wood preserver too.

[Jay Greer]

Rather than speculate on your concerns, I would recommend that you contact some experts who have sound knowledge in this matter.
Stan Bishoprick of Legendary Yachts has built several replicas of Herreshoff designes over the last fifteen years using composit construction. I would think that he would be the, current most knowlegable person to give you an opinion. Stan's address is:
Legendary Yachts
PO Box 26
Washougal WA 98671
Phone: 360-835-0342
Fax: 360-835-5052
E-Mail: sbishoprick@uswest.net
Boat Lengths: 33' - 72'
Manufacturer of wooden sail boats

Another source of information as to expansion factors of wood by percent of moisture content is the US Forest Products Lab:
http://www.fpl.fs.fed.us/documnts/fplgtr/fplgtr113/fplgtr113.htm
Sounds like you have one of the most sought after white oak timbers.
I envy you!
JG

[emichaels]

This is for the Hess boat, right? Or have you switched to the Herreschoff?

Look for an invite to our Caroling party on the 23rd. :)

Steven


Yeah this is for the Hess 30' cutter. Just got back from the sawmill this afternoon and completed my collection of timbers. Found another flitch exactly like the first one. Perhaps sisters .. And a beautiful Angelique timber for the entire tail end of things. All set, stay tuned, in about 100 years I should be done.

I agree with some posts that its probably not something to worry about to much. The worst that can really happen, knock on wood, is the first season the garboards crack and leak. So when I haul it, I'll fix it.

I like Bob's idea of checking the MC of some keels that were just hauled, going to do that this weekend. That way I can at least predict the possible movement.

Eric

[emichaels]

Jay, Thanks for the links. Based on the formula in the handbook it looks like the majority of the shrinkage happens in the oven. The last 8-14% of MC being driven out.

I went to Freeport marina this morning and was fortunate enough to go aboard an older woodie , becasue the owner was there scraping the bottom. Measured the keel timber and any other timbers I could access and pretty much across the board the white oak came in at 20-24%. The top of keel, though dry to the touch, measured 24%.

The outside seems less reliable due to the many layers of paint. Seems that a portion of the measurement would be the MC of the paint itself. Nonetheless the number there was 29-30%.

In some locations this number would actually only be inches away from the top of keel and so this lead me to believe the paint itself was contributing to the reading.

Edited to add: The owner did say that 10 years ago or so when he had the boat professionally scraped to bare wood and repainted they coated the entire BWL with very thin epoxy. completely saturating the outter surface 2 times. In his opinion he thinks the paint holds up better after this treatment than before the treatment.

Eric

[Bob Smalser]

See if a friend or local builder has a slide hammer meter with longer pins. Figuring how much the wood will move across and with the grain is the easy part. Obtaining good baselines to begin with isn't.

http://pic20.picturetrail.com/VOL12/1104763/3075040/214182916.jpg

[Thad]

What is the timber in question, I don't see mention or question.

[Bruce Hooke]

Jay, Thanks for the links. Based on the formula in the handbook it looks like the majority of the shrinkage happens in the oven. The last 8-14% of MC being driven out.

Yes, my understanding is that shrinkage does not start to happen until the wood reaches the fiber saturation point, which is around 28% for most woods. This does raise the (minor) point that the equation for shrinkage grows less accurate as you move up into the 20% and up range because there is some variation in the fiber saturation point in different woods and the effect of this difference on the calculations is greatest when you get closer to the fiber saturation point. Or so I understand. I think everything I've said here is found in R. Bruce Hoadley's Understanding Wood, which is an excellent book.

However, I would not worry too much about the above. I doubt it could make enough difference to really matter.

[Thad]

There is considerable difference between woods in dimensional stability. How much swelling occurs in different fully cured woods is a question.

[emichaels]

What is the timber in question, I don't see mention or question.

Thad,
The timber I am wondering about is the keel timber. 5-1/2 molded x 16 sided, 21' long (at dims it will be when working it into the assembly.)

Looking at the original question I asked if the garboards are likely to split out after launching, since the bronze floors will hold the frames stationary and the keel will swell outboard.

Actually all of the timbers, WO at least, are form the same supply. So they are all air dried down to 20% . The Angelique is only about 3 years old.

Eric

[Thad]

Is that timber WO or live oak? If WO air dry to 20% flat sawn and returns to its green dimension when wet (I am not sure of that holding) it might spread by 1/2 inch over 16" (3%) or 1/4" each side. By the way, the 5 1/2" dimension is the sided, 16" molded. I would expect this swelling to put tension on the floor fasteners, but pressurize the garboard joint. Oak swells slowly so the planking will have time to adjust.

[emichaels]

White Oak

[emichaels]

By the way, the 5 1/2" dimension is the sided, 16" molded.

Lyle Hess has these label "5-1/2 molded" (verticle dim in profile), and "16 sided" ( athwartships).

Eric

[Thad]

We understand the meaning, but . . . . The 16" dimension is molded, i.e. that is the maximum with shape cut (molded) out of it. 5 1/2 is the planed (constant, except perhaps for fairing bevels at the ends) thickness of the piece. (My understanding. Mr Hess may come from a different tradition, California? or I may be wrong.)

[emichaels]

This is very helpful for novices, such as myself.

Credit goes to "mmd" in an older thread I just found to help me understand.

Love the picture.



QUOTE=mmd]Imagine a line in space that runs fore-and-aft in the exact middle of your boat. Now you assemble all the bits and pieces that makes up the boat around this imaginary line. If the dimension of any given piece goes toward the line in the middle of the boat, it is moulded to the shape of the boat and is the moulded dimension. If the dimension runs along the (out)side of the boat, it is the sided dimension.

http://www.boatdesign.net/gallery/data/500/medium/SIDED-MOULDED_JPEG.jpg

For parts that lie 'thwartships, the moulded rule is applicable, so the thickness fore-and-aft is then obviously the sided dimension. So the floor in the illustration above is moulded 3" and sided 3/4".

Of course, there are exceptions to every rule. According to the conventions I have just explained, the washrail that borders the cockpit should be termed as being moulded 3/4" and sided 3", but every builder I know refers to it as just the opposite. I guess it makes sense if you consider that it is "moulded" around the cockpit opening.[/QUOTE]

[Thad]

One more effort. Sided/molded is a functional distinction (often) used by designers to aid the builder in ordering and preparing stock for building. Sided is the dimension to which stock is planed for shaping to the molded shape, the molded dimension being the constant or maximum dimension of the formed shape. Bent ribs are defined in the same way as sawn frames. Stems are sided side to side and molded fore and aft, while flat laid keels are sided top and bottom and molded side to side. Siding is planing in this terminology. My understanding, from looking at lots of plans and lots of specification lists. Have fun.

[py]

Mate, they been building boats for hundreds of years. Stop worrying and get on with it. Your keel will try to expand a bit, every plank will try to expand a bit. Will it all pop off the frames? Will it destroy the frames? Nope, there'll be some stretching and some squeezing, and you'll end up with a nice tight rigid stressed hull. Its all good.

[Thad]

Right. Not that it's bad to think about things. Since boat structures have been pretty well tested and metal floors have been successful on thousands of vessels and well cured timber is recommended by most authorities, proceed with confidence and have fun, building and sailing.

[Bob Smalser]

...they been building boats for hundreds of years. Stop worrying and get on with it...


Right. Not that it's bad to think about things.

For hundreds of years labor was cheap...they used building crews and the boats went in the water relatively quickly....within a year, at least....even today.

A single, weekend builder today takes severalfold as long from timber selection to launch, with the timber reaching equilibrium with the air, not the water, at the rate of one dry season per inch of thickness, regardless of gravel and sawdust.

Monitor your moisture contents so you can predict problems.

[emichaels]

Bob,
That is what I will do. I am still wondering what is the best method of "treating" the WO while I build over the next few years. It will be easy enough to keep it from drying any more, but what would be the correct way to actually add some moisture that will stay till launch.

Once I shape the timbers dosing them each week or so with linseed oil before red leading ??

Eric