Scarfing white oak keelson

[Doug Tindal]

I am replacing the longitudinal plank ?keelson? in a 12' plank skiff.

The original is about 12' long. The replacement will be made of two six foot sections 5/8" by 5". How do I scarf the two pieces together? What is the ratio on the angles of overlap? I've been told it should be 8:1. What set up should I use to make the cut? I see advertised jigs for cutting plywood scarfs with a planer. Are they appropriate for solid wood.

I have this feeling that somewhere in an old woodworking mag is an article on how to do this with old razor blades, a model T chassis, recycled wine casks.........or maybe there's a wiser head than mine right here!

[Jim Ledger]

Is there a compelling reason not to make the replacement out of a single plank?

[Mrleft8]

Check out a book called "The Art of Japanese Joinery" for examples of scarfing planks.

[Doug Tindal]

Is there a compelling reason not to make the replacement out of a single plank?

The boat's in Maine, I'm in Massachusetts, and I have two beautiful dry 7' white oak shorts ready to go, if it's not too much trouble to scarf them.

[Doug Tindal]

Check out a book called "The Art of Japanese Joinery" for examples of scarfing planks.
Thank you! I'll look for the answer there.

[Jay Greer]

While I am an advocate of all phases of Japanese joinery for many kinds of construction, I would rather guide you to another book, "Boat Building" by Howard Chapelle for a more practical form of scarf joint. I would highly recomend a 12:1 scarf that is glued with resourcinol for your keel.
Jay

[P.I. Stazzer-Newt]

While I am an advocate of all phases of Japanese joinery for many kinds of construction, I would rather guide you to another book, "Boat Building" by Howard Chapelle for a more practical form of scarf joint. I would highly recomend a 12:1 scarf that is glued with resourcinol for your keel.
Jay

Books on japanese joinery have a sort of dreadful fascination - buy it, read it, enjoy it - if it inspires you then go on and learn the how-to.

Meanwhile, Jay's suggestion has much merit.

If you can use a hand plane just clamp the boards side by side, and make the two cuts at the same time.

[Jay Greer]

Books on japanese joinery have a sort of dreadful fascination - buy it, read it, enjoy it - if it inspires you then go on and learn the how-to.

Meanwhile, Jay's suggestion has much merit.

If you can use a hand plane just clamp the boards side by side, and make the two cuts at the same time.
Indeed that is one way of doing it. A further step is to stagger stack the two planks at the correct distance for the scarf. The preliminary cuts can be made with an adze and finished with a plane.

Just a note of support for you here for Japanese style joinery. For over thirty years, I have used Japanese tools, almost exclusively, in my work. I do find the Japanese form of joinery to be both fascinating and practical. Again, it just isn't as practical here for a Western keel scarf.

For an a couple of interesting joints, check out the double haunced mortice, mitered and tapered draw pin hand rail joint for porch railings on houses. Or, the hammer head scarf. They are fascinating and fun to layout and construct.
Jay

[Jim Ledger]

No joint, no matter how well designed or skilfully made can even approach the strength of a single piece of wood. Furthermore, in this case the time spent making the joint will be worth more than the wood itself.

Since White Oak is relatively inexpensive and easy to come by, if it was me, I'd just buy a new piece of wood and use the short planks elsewhere.

[Doug Tindal]

I would highly recomend a 12:1 scarf that is glued with resourcinol for your keel.
Jay[/quote]

Geez! 12:1 !! I think I just saw the 'compelling reason' Jim asked about! My poor cabinetmaker skills are not likely to result in a tight joint trying to keep a flat plane on two hand cut surfaces overlapping by seven inches, at least without some jigging.

Actually sounds like a challenge that would be fun to take on, and the japanese joints sound way interesting. But I am going to take Jim's advice and buy a plank to the right length next time I'm up north. Gotta get this boat into the water someday.

She's about 85 years old, was put in a barn and forgotten until I took her on about 3 years ago. I thought she was solid when I took her down. Her bottom planks had dried out and the gaps between planks were a half an inch in places, and many of them were cupped. So, says I, An exercise in replanking! Goin to school here...

Instead the project has perhaps been more an object lesson in why it might sometimes be wiser to just use a rescued boat for patterns, etc. rather than repair trying to preserve original fabric. I could have built her anew with the time spend fussing with original fabric.

The fundamental thing I missed, which you guys would no doubt have caught, was that she was thoroughly nail sick, having been put together with galvanized nails. The oxidation had attacked the two side planks (the one part of the boat which I could not replace without destroying/totally disassembling the boat) so that when I drove new nails for the new bottom planks, in some places the nails wouldn't hold. Why I didn't walk away, I don't know.

Here's the stubborn fool part. I then injected Git Rot into the side planks from below under pressure, and now I'm adding reinforcement planks to the sides on the inside (doubling the nailing surface available). If I eventually lose her to rot, I've taken her patterns in the meanwhile, and I'll build her all over again if it kills me.

This boat has been through it all, and I think the only reason she's survived all these years is that she was originally named "Wet Fanny" and no one had the heart to take her to the dump. Brings up images of people rowing her around in bloomers and parasols or such like...

I'm very glad of the fellowship here and thank you for taking the time to reply to my query.