New (to me) canoe and a question or two.

[NorthCountryWood]

Hello. Long time lurker, first time poster because I finally got a canoe.

1957 18' CS Otca. In good condition (compared to most I've seen for sale) but could use a little love. The previous owner gave me the build record, specs and decals, original seats and a lot of extras. It cleaned up with a washing, but needed a few coats of paint and varnish. It had a blister/bubbling issue when I first washed it, but hasn't come back since the new paint and varnish.

Not planning a recanvas and repair for a few years unless something goes horribly wrong. The plan is to enjoy it a bit first.


On to it then...

My question is about the thwarts. Only one of the three installed appears to be original but one of the ends is hacked up so I'm not sure if it's the correct length. When I removed all of them for varnishing the sides spread a good 3-4 inches and needed a fair amount of muscle (a clamp would've been easier/smarter) to reinstall. Is this normal?

I read in the spec sheet that it should be 37 inches "Width Extreme". I assume that's at the widest point. I replace the outer gunwales with generic cheapo 3/4" ones. I'm measuring from the outside of those and hit right at 36" with the non-original center thwart installed.

So either my gunwales are too narrow or the thwarts are too short, or (I think) a combo of both.

5/4 gunwales would get me to that number. Seems a bit much, not to mention tough to steam bend, but then what do I know?

I also noticed splits in all the thwarts at the bolt holes and in the only original thwart opposite the buggered end. Could it have been shortened due to a split?

I plan on fabbing up 3 new thwarts, the center a carry thwart, and wondered what the preference for stock width and material is? The current 2 ash, 1 maple are all 4/4 stock and all split at the bolt hole.

I have quite a few books on wood/canvas canoes, but all are a bit dated. No offense to the authors. I know I've seen at least one of them on here. Honestly, these books are in my "constantly re-reading" library. I just wondered if there are updated suggestions about materials/techniques for this issue.

Thanks all,
Robert

 

[Andre Cloutier]

I have quite a few books on wood/canvas canoes, but all are a bit dated. No offense to the authors. I know I've seen at least one of them on here. Honestly, these books are in my "constantly re-reading" library. I just wondered if there are updated suggestions about materials/techniques for this issue.

Just my 2cents but with the exception of some modern adhesives, paints and tools etc wood/canvas canoes are themselves dated. Luckily for us 100+ years have served to rid a lot of the necessity of trial and error. I'm heavily into traditional archery, and not much has come along to improve the stick and string either, but the tools to make them are nicer.... Congrats on acquiring the canoe, see if you can stop at just one....

 

[Dave Wermuth]

a hint

use 4 bolts at the center yoke, two at each end. Much more stable. Should hold better. As far as width: I'd try to get to the standard OTCA width. BUT As you pull it in stand back and make sure the line is fair. YOu don't want an hour glass shape on a canoe probably. Same thing with the quarter thwarts. Sometimes the thwart hole will bust out to the end. (Which makes it a slotted thwart). Should still work. I like gunnels to start at 7/8" which may seem a little stout but by the time the angle is cut for the tumble home if any then it ends up less. And then too, when you round them over they look a little smaller. I had a canoe open up quite a bit with out the yoke. not a problem. My 18' HW has five thwarts. A center, two quarter, and two 'hand thwarts at the ends.
Congratulations on your acquisition.
Regards, Dave.

 

[NorthCountryWood]

I like the 4 bolt center thwart idea and the extra carry thwarts on the ends.

It seems that the corners of the square nuts on the diamond head bolts with are kinda buried in the bottom of the thwarts. Either they weren't tightened and dug in at an angle or they were over tightened. Each indentation corresponds to a split. A few washers could possibly help prevent this in the future.

Actually, when I took it apart the diamond heads themselves were pretty well dug into the inner gunwales. This could have caused the loosened nut and subsequent movement and split.

Interesting.

 

[Dan Lindberg]

When I do/build my carrying yokes, I make brass plates that I put both top and bottom, like large washers to spread the load to the rails and yoke.

Filing the holes square to match the standard fastener (either OT diamonds or carrage) is a bit of a pain, but the rails and yokes like them.

Dan

 

[mark wismer]

I like the 4 bolt center thwart idea and the extra carry thwarts on the ends.

It seems that the corners of the square nuts on the diamond head bolts with are kinda buried in the bottom of the thwarts. Either they weren't tightened and dug in at an angle or they were over tightened. Each indentation corresponds to a split. A few washers could possibly help prevent this in the future.

Actually, when I took it apart the diamond heads themselves were pretty well dug into the inner gunwales. This could have caused the loosened nut and subsequent movement and split.

Interesting.

I had loose bolts & the diamonds were just starting to sink in. We took out each thwart, one at a time and found the holes were sloppy but not really elongated or cracked. We had some .005 brass 'shim' stock that we cut and wrapped around the bolt to make a brass spacer inside the theart ends. they were a little proud so we 'peened' them over. We made similar spacers for inside the inwales too but sized to fit. The bolts tightened up w/ out sinking in...and you can't see it!

I agree on the 4 bolts per carry thwart for extra stability & strength. Isn't the carry thwart usually placed ahead of center?

 

[Douglas Ingram]

Max width with a canoe with tumblelhome is not the same as the gunnel width. With tumblehome, the gunnle width is narrower than the max width.

4 bolts for the center! helps reduce the torque on the thwart while portaging the canoe.

Yes, its normal for the canoe to spread some with the thwarts removed.