Unseasoned timbers

[Glider]

Hello,

I'm building a heavy displacement boat, LOD 37', planked (George Buehler design). I need 10x10 timbers for the backbone. I cannot find seasoned timbers of required size. I don't want to laminate them, also. All I can get is green timbers with heart (pith) in them.

The boat will be on the water full year. What if I do the following?
1) Cut my keel and deadwood pieces from green timbers, and assembly them, steel green.
2) Apply heavy doses of sealant regularly (linseed oil+terpentine?), every week or two probably, until saturated.
3) When not in work, cover timbers/assembly with plastic film tightly.

I think this should protect timbers from drying out during construction time. And after the launch, the timbers will be soaked with water anyway.

In the "How to Build a Wooden Boat" book by David C. McIntosh it's recommended to use green lumber for the keel, to prevent swelling when the keel soaks water. Despite of this, I would certainly use dried timbers - if I could. However, _I can't_. So I'm trying to find a solution.

Will appreciate your help!

[Bruce Hooke]

It is almost impossible to dry a 10" square timber -- it would take years. That is why you can't find such. However, it is usual to use green timbers. I will leave it to others to discuss the right ways to seal the timber.

HOWEVER, including the pith in the timber is an issue. You are certain to get a splits or checks going in to the pith.

[Bob Smalser]

First of all, there's no such thing as a dry 10" timber except in barns. Nobody can afford to season them a decade or more, and neither did our forebearers. They used them green or partially seasoned.

Freshly-milled heartwood will run 30-60% moisture content, depending on species....hardwoods on the high end and softwoods on the low end of that range. Your submerged keel will stabilize at around 25% for the harder softwoods and up to 30% for the oaks. This means you need to control drying during construction so you come as close as possible to the ideal moisture content for the wood you are using.

In the shop, pack your timbers in damp sawdust while they aren't being worked on, to slow drying. By the time you get to keel assembly, they'll have dried a surprising amount on the surface, with the core still be quite wet. Leave them exposed indoors and they'll check on the surface due to fast, uneven drying. The optimum schedule is to stack and sticker them outdoors for their first 6 months, a year or more before bringing into the shop:

http://pic3.picturetrail.com/VOL12/1104763/3075040/31637369.jpg

At assembly, prime all the timbers, to include inside all the joints, with thinned red lead paint. This will assist in slowing their drying and is all you need to use until time to paint.

When selecting your timbers, insure the pith is dead center in both ends of the timber. If the pith is off center on one or both ends, or spirals along its length, the timber is sure to warp in drying (and probably after all the work of assembly).

[ 11-15-2005, 10:38 PM: Message edited by: Bob Smalser ]

[George Roberts]

I see no reason to dry the wood but ...

If you need to dry large pieces of wood, RF or vacuum kilns do a nice job in a reasonable amount of time.

[Thad Van Gilder]

I love beughler designs... I always wanted to build myself a Olga with the gaff ketch rig.

If you soak down the timbers with linseed oil, pine tar, turps and japan drier, it will help keep down checking.

-Thad

[Glider]

Almost clear, thank you!!!

Assuming that I cannot wait for 6 months or so to partially dry timbers, I'm going to do the following:
1) Buy green timbers.
2) Keep timbers in dump sawdast while not working on them.
3) Cut keel parts.
4) Apply preservative to the parts.
5) Apply boiled linseed oil/terpentine mix to the parts.
6) Paint jointed surfaces with thinned read lead premier.
7) Assemble the keel.
8) Paint the whole assembly with thinned read lead premier.

Did I got everything right?

[ 11-16-2005, 12:01 PM: Message edited by: Glider ]

[Bob Smalser]

I'd drop the preservatives and the linseed-turps in favor of thin red lead.

Wet wood will only absorb so much, and what it absorbs you want to be the most effective. Red lead is a biocide in addition to a sealer, and is more effective than the copper preservatives most ofen used today.

[Glider]

Bob, thank you! Understood.

[Stephen Hutchins]

Another method to prevent checking (or wood becoming too brittle in the case of veneers) in dry shops is to lay a cloth over the wood and place a humidifier under it, For backbone pieces, specifically, I think fresh wood shavings is better.