Gunwales

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WMegl
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Gunwales

Post by WMegl »

I have 3 questions:

I wish to attach my yoke using John Michne's mortise and tenon technique. My inwale is made of walnut and it's dimensions are 3/4 in. wide on the bottom, 5/8 in. wide on the top (it's beveled to match the tumblehome), and 13/16 in. high. Following the rule of 1/3's for a mortise and tenon joint, the tenon will be 13/48 in. thick, and the wood above and below it in the mortise will be the same. Do you think this will be enough material for a strong joint? If not, I could epoxy glue a block underneath the inwale in the yoke area to make it thicker.

CC does not mention steaming gunwales. I have seen it mentioned in another post for the Redbird because of the shear's curve at the bow and stern. I am building a Redbird and have formed and clamped my inwale in place. It is made of walnut, the last 32 in. at the bow and stern have been beveled, and the entire length has been beveled to account for tumblehome. I have not yet cut the scuppers. A considerable amount of force is required to clamp the last 12-14 in. of the inwale along the shear line. I can't see the #4 X 1/2 in. screws holding it in place although the final installation includes the epoxy glue. I had planned to install the inwale initially with the screws only while attaching the yoke.
If steaming is recommended, do you steam one end at a time, does steaming effect the length, and do you use the hull as the form, or do you make a jig for the steamed inwale to dry to prevent damage to the hull from the hot wood?

Does anyone have a recommendation for spar varnish? My only experience is with MinWax. I have seen Epifane mentioned in the BF.

Thanks.

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Cruiser
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Re: Gunwales

Post by Cruiser »

As far as strength goes, once you epoxy the yoke in place, you can consider the whole joint as a single piece, epoxy is that strong.

I have used a couple of varnishes, now that I have tried Epifanes, I likely won't use anything else, I really like it.

If you can get the inwale into position and clamped without steaming, that's the route I would go ... if you have to steam, it will be quite an operation to do. I haven't found any dimensional issues with steaming ... but you really need to get that temp up or it just doesn't work. If you have the facility to steam and want to shape it to fit easier, it will make attaching the gunnel a bit easier, but it is usually at least a 2 person job, so you will have extra hands anyway, so steaming is a bit of a luxury.

These are just opinions, I am sure you will get lots of other input.

Just a point about permanently installing the yoke, if you want to try a different style, or it needs to be replaced, you will be in for a lot of extra effort to make that happen. It has a good look, but if you get it wrong, you pretty much have to live with it.


Brian
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WMegl
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Re: Gunwales

Post by WMegl »

Brian: That's a good point about wanting to change the yoke design. I hadn't considered it. However, I don't think it likely I would want to change it in the future. Once this craft is built, I'll be using it as is until either it or I fall apart (most likely "I").

I didn't have any trouble steaming my inner and outer stems. I will need to have the steaming tube horizontal to heat the end of the longer inwale. However, in your opinion, the epoxy (I'm certain the #4 X 1/2 in. screws won't) will hold the forces created by bending the walnut.

Epifanes it is.

Thanks for your help.

Wayne

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Patricks Dad
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Re: Gunwales

Post by Patricks Dad »

Another vote here for Epifanes. It's all I use. My first build was a Redbird. I used cherry for my gunwales. I haven't read Canoe Craft for quite awhile but I'm pretty sure there are directions in there for steaming gunwales. As noted there, I cut a form out of a 2X6 (with a curve a bit tighter than the shape of the sheerline to allow for some relaxing). I steamed and bent one end of both gunwales at the same time and then steamed the other ends together. I soaked them for 24 hours before steaming. Once steamed and bent, they were fairly close to matching the sheerline shape and putting them with just thickened epoxy worked just fine (no screws).

The strength of the epoxy joint (if done right) will be stronger than the wood. But as Brian noted, make sure you like what you glue...
Randy Pfeifer
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Patricks Dad
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Re: Gunwales

Post by Patricks Dad »

One other note. I would install the inwales completely before the yoke. And if you can readily bend the gunwale to match the curve of the sheer, you might get away without steaming.
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WMegl
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Re: Gunwales

Post by WMegl »

Randy & Brian: Thanks for your replies.

I can install the inwales using clamps, but John recommends assembling and gluing the inwales and the yoke prior to installing the inwales. If I choose to do this, I think I will steam the inwales to make installing the inwale/yoke assembly easier.

Again, thanks.

Wayne
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Glen Smith
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Re: Gunwales

Post by Glen Smith »

I would prepare the mortise and tenon joints but I would not glue the inwales and yoke together beforehand. It has happened to some builders to snap an inwale while bending to follow the sheerline. With everything glued together, you are up that proverbial creek. I have used this type of joint on one build and I installed a spreader stick to open the hull wide enough to be able to install the yoke then removed the spreader and the hull worked like a clamp to create a tight joint while the epoxy set on the yoke ends.

I also adopted Epifanes as my only varnish.
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Patricks Dad
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Re: Gunwales

Post by Patricks Dad »

I wouldn't even cut the mortise in the inwales before installing them. Building a 2-inwale + yoke assembly before hand is a headache to assemble, handle and unnecessary. As Glen notes, it also add some risk. Further, you need to identify the correct balance point for the finished canoe before the canoe is finished. I suggest installing the inwales, decks and seats before identifying the exact right spot for the yoke. After you have the right placement (by clamping it in place temporarily and carrying it around a bit), you can install the yoke. I use a biscuit joiner make the joints.

You'll be disappointed if you build the yoke into the assembly first and find out later that you really wish it were 2" fore or aft of it's eternal resting place....
Randy Pfeifer
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WMegl
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Re: Gunwales

Post by WMegl »

All: Very good points. I was going to assume the CG wouldn't change with the installation of the inwales, outwales, and decks because they're all symetrical. I was going to calculate the moments created by the seat locations to calculate the new CG then install the yoke a couple inches in front of it. But, having read your posts, I think your experience prevails. John Michne is an experienced builder with skills that far exceede mine. I'll play it safe.

Thanks for your help!

One other question. CC gives an equation to calculate seat position for 2 paddlers with different weights. It involves 2 independant variables which can't be solved with one equation. So, I assume you determine the location of one seat based on preference, then solve the equation for the other seat location.

Wayne
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Jim Dodd
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Re: Gunwales

Post by Jim Dodd »

Hi Wayne
When I locate my seats, I first make sure there is enough leg room for the bow paddler, and then set the stern seat accordingly.

Jim
Keep your paddle wet and your seat dry!
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WMegl
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Re: Gunwales

Post by WMegl »

Jim: Thanks.

All: Now I remember why I wanted to locate the yoke now. I want to cut the scuppers prior to installing the inwale have a non-scuppered space for the yoke. Do I guess on a location for the yoke and leave extra space on either side of it non-scuppered?
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Patricks Dad
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Re: Gunwales

Post by Patricks Dad »

Yes.. Leave a good scupper-void to ensure your yoke will not stumble on a scupper...
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Re: Gunwales

Post by BearLeeAlive »

Patricks Dad wrote:Yes.. Leave a good scupper-void to ensure your yoke will not stumble on a scupper...
Imagine someone with no knowledge of canoes reading this sentence. :laughing
-JIM-
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