Thursday, May 19, 2016

Making A Portage Yoke

Two of my three canoes came with portage yokes.  The Superior Expedition has an adjustable tractor seat, which if you remove it and put it back in inverted, a portage yoke was fitted to the bottom side of the seat.  My ultra-light Kevlar Hornbeck 14 also came with a removable cherry portage yoke which quickly attaches to the gunwales with bolts and wing nuts.  The Mohawk Odyssey 15, however, has no yoke, and being made of Royalex, is substantially heavier than the Hornbeck.  There were two solutions.  The first is to buy a yoke and mounting gear ($95.00 + shipping for an ash yoke and gunwale hardware from Piragis; or, from Jem Watercraft, the gunwale mounting hardware is $40 alone, without a yoke, or $57 for both yoke and hardware.). Or secondly, make a yoke and buy your own hardware.

This is the whole pattern with the panels taped together and transferred
to the rough-sawn wood.  If needed, you can zoom in for closer inspection.

The first necessity was making a pattern for the yoke.  Neither of the yokes from the other two canoes, due to their proprietary design, would work as a pattern for a classic portage yoke.  Jem Watercraft, however, does have a free pattern for making a yoke.  There is one little wrinkle you need to take note of.  For the pattern to be printed to scale, the printed pattern panels, of which there are five, need to measure 9-inches in length.  The first time I printed it, the panels measured 8 13/16”.  When I realized the printer was set to “fit” rather than “actual size”, just clicking “actual size” corrected the problem.  Not checking the scale will obviously make your pattern useless.  The pattern is printed as five panels, which you assemble by just joining the patterns, A to A, B to B, and so on, and taping them together.

Then, there’s the choice of woods.  Ash is the most common, but cherry is also listed as a choice for those who care more about aesthetics.  My choice was simple.  I have zero ash in the shop, but about 1,000 board feet of cherry, so cherry it is.

The pattern will give you a long yoke that you can cut to length 
to fit your canoe.  This has been planed, had the edges rounded 
with a 1/2 inch router, and pre-shortened a bit.  A bit of wood was 
left for final fitting, as the Mohawk has both sheer and tumblehome.

Here the pattern transfer is done with a sharp stylus, awl, or tack.  To transfer the pattern to the wood, I use two methods.  To transfer a pattern to planed wood, I use carbon transfer paper.  If the wood is rough finished, you can either plane first, or with a hard wood, like cherry, getting rid of most of the wood makes the planing that much easier.  Make a series of dotted perforations along the pattern lines, remove the pattern, and pencil a line to join the dots.  For transferring patterns to smooth wood, there are several techniques illustrated on You Tube.

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