Boundary Waters Quetico Forum :: Group Forum: Do It Yourself Gear :: Prism portage yoke
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portagedog09 |
pd |
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Traveler |
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portagedog09 |
pd |
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Traveler |
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Traveler |
I think it works. I only tested it with a short walk around the yard and it is still held on the canoe with temporary clamps but so far so good. The weight is 28.5 oz without varnish or permanent clamps. |
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Traveler |
Okay, portagedog, here is an idea. I would be glad to know if you think it has any merit. If my drawing is unclear or the photo is bad I will try again. My idea is to make a typical clamp-on yoke out of ash or basswood or something with some kind of typical clamping system. In order to gain headroom I am considering the idea of "struts" that mortise into the yoke and rest against the seat slider bars for support. I haven't thought far enough along to have a plan for exactly how the pads attach to the struts. I have no idea on weight but I suspect the struts can be narrowed a bit and still be strong enough. Any thoughts on this? |
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Traveler |
I have already begun a trial build so I will continue and see how it goes. My thinking about weight was that by making use of the seat rail for additional support I would have something like a little truss that would allow me to use thinner wood. I decided to use 1/2" poplar that I had and see how it goes. My Prism only weighs about 30lbs so we'll see. I will post some pictures if I make enough progress to believe it will even work. I don't know if poplar is a stupid choice — it's what I had. Trial and error. :-) Thank you for the good advice! |
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portagedog09 |
Traveler, I understand your drawing and what you're trying to visualize. There's a thousand ways to skin a cat and if it "works" it's not wrong, just different. It looks like you're trying to combine the Wenonah style pedestal mount with a clamp on gunnel mount yoke. What I'm not seeing is the benefit of that. It seems to add complexity unnecessarily. And probably weight. It'll also be 'bigger' than either of the other designs by themselves and I'd be concerned about the 'legs' or struts getting caught up in something when not attached and potentially damaged. Another thing to consider is the higher you make the mount for the actual pads, the larger that lever will be and it will need to be stronger to withstand the amount of torque load on it. How much I don't know, as I've not tested anything like that but mathematically it makes sense. I'm sure it could be successfully done, but I made the choice to go with a lower mount/taller pad for two reasons - less complex and lower weight. MP's original design that he made used some hollow boxes that the pads were then mounted to and it worked but was more complicated to make and a lot less elegant of a design (sorry MP!). You can get some appropriate glue and assemble a taller or thicker pad that should last - just understand that the glue joint will probably not be as flexible as the rest of the pad - and that may be just fine for how you intend on using it. I had thought about doing that too but just didn't like having to do that when I knew there was one piece stuff available. One thing to keep in mind about your stadium seat foam - or any foam - is the compressibility of it. How far does it compress with a given amount of weight on it (the canoe) before it stops compressing and takes a load. I think you really only want it to give enough to be comfortable on your shoulders. As MP metioned, the EVA I used is a bit stiffer but the way it's curved, keeps the load centered and spreads it across the shoulder better than a flat pad. FWIW. Regarding wood choices - basswood is a very soft 'hardwood' as compared ash, cherry, oak or something along those lines (and more porous). I think you would have to go with a thicker piece to get the same level of strength. I did some comparisons of weight per cubic inch of several hardwoods vs. pine (much lighter) and for the amount of wood used, there was not a significant weight difference and so I go with the harder, stronger wood. pd |
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Traveler |
The jury is still out as to whether this design has promise. So far so good, I guess, but until I attach pads and get it on my head I really have no idea. Regarding the use of poplar I have done some research. Clearly not the best choice but from what I have learned it may have the strength for this application. My only "test" was to try to bend the yoke around my knee. Regarding water resistance poplar will require a lot of careful babying. This version is more or less a model to test the design. If it shows promise I might try to make one out of ash or birch. On the other hand as I live in Arkansas and only get to the BWCA once every year or two I do not put a lot of stress on my equipment. The yoke I have on my '62 Thompson I made out of untreated 3/4" plywood and it has lasted 35 years. :-) I'll let you know the results when/if I actually get this thing on my head! |
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Traveler |
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MagicPaddler |
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MagicPaddler |
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portagedog09 |
I've made several and in that thread is a very nice, strong one I made for Magicpaddler's Rapidfire solo from cherry with quick release cam clamps. I have a much simpler version on my Merlin II in ash that weighs in at 28 oz. with EVA foam pads and is very durable. Getting the right hardware and having the tools to do it is the key. If you feel over challenged, I could be persuaded to help out. Good luck. pd |
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Traveler |
If you were making another one would you still go with the very thick foam blocks to achieve the height or have you thought of alternate builds that you might prefer next time around? |