I have a 20 lb canoe, and want to make a lightweight yoke for it. The yoke will need to be 30 inches across. I’ll also drill holes in it to mount the shoulder pads. I’d like to shape it in a curve around my neck instead of just a straight rod.
What light weight wood can I use to support that weight?
would metal like aluminum be lighter, but how would I shape it?
would a carbon fiber sheet that I can saw out a shape work? where do I find proper carbon sheets for NOT a lot of money?
Wood strength largely correlates with density so you likely need some type of hardwood. Ideally in wood you might want to laminate strips of hickory bent to the shape you desire. For a solid piece I would suggest something like white oak which has excellent rot resistance.
Using metal is will probably be a problem unless you sue a straight piece of aluminum tubing. You can put a wooden plug in each end that allows you to connect to the sides of the canoe. I’d recommend a larger piece of wood with a hole for the tube to spread the load on the sides of the canoe. BTW: what is your canoe made of? 20 lbs. is pretty light.
A carbon fiber sheet won’t work. On it’s own it has little strength. You would have to create a laminate of carbon fiber and something like foam. This would likely not turn out the way you expect and might cost you a lot for the materials to create a finished usable part.
A simpler option would be a nylon web strap attached across the canoe. Cover it with some soft foam tubing for shoulder pads. You can even use a tensioner to adjust the length. You could just add hook eyes to the canoe so it is removable and you can attach other straps or ropes for stowage, dragging through shallow, or attaching to the top of your car.
Among the best species are Douglas-fir and Sitka spruce.
Unless you are skilled at composite work, you’d do better to look at carbon-fiber tubes. But these are likely to be a lot more expensive than wood for only a small reduction in weight.
OP is unlikely to be shaping aluminum tubestock or carbon fiber and probably not set up to carve much wood, either. The neck/shoulder part is going to be most comfortable and easy to build from flexible straps of some kind.
I’d start with something ready-made. An ALICE backpack frame seems a little overkilly but illustrates the point.
Googling, ready-made canoe yokes are available, for as little as thirty bucks or so. Most seem to be shaped wood (i.e., cut to shape) rather than bent.
I’ve got one of those, but it is relatively heavy compared to the boat. Its a 10.5 ft kevlar hornbeck listed at 15 lbs. I can carry it easily with one hand but for longer portages, I was considering a yoke.
But my yoke seems to weigh 3-4 lbs, which seem silly to have a yoke weigh so much compared to the boat. I can sacrifice a lot of strength from that yoke as its designed to carry 60-80+ lb boats, I can probably get by with one that is half the strength and weight.
One material you might consider is electrical conduit. It is lightweight, won’t rust, is bendable under the right circumstances, comes in a variety of diameters, and has lots of ready-made accessory bits that you can MacGuyver to your needs.
There’s a likely a whole aisle of conduit, tools, and accessories at your local hardware store.
You’ll see there’s a bending tool - long handle, quarter round bending guide as the head. It’s designed to keep the conduit from crimping when you bend it; all you have to do is work your way along your length to set the bends you need.
the accessories like end caps, hangers, and so on are likely a rich resource for sorting how you’d make a releasable attachment to the canoe
and, I bet that the inner diameter of pool noodles (or pipe insulation since you’re already at the hardware store) matches nicely to conduit and makes for shoulder protection and oh-no-I-dropped-it-floatiness.
There’ll be a lot of how to videos on bending conduit to while away your evening, but you might also consider trying it flat on a workbench. I’m not sure what the proper term for this is (anyone?) but you’d place a couple of upright pegs to brace the length, then bend to the form you need by adding more pegs as you go. This would help keep all the bends in one direction if that is critical.
I bet you can even make some curved blocks of wood to set in the peg holes that would keep the conduit from crimping. People who really like spending as much time on the jig as the end product will appreciate this… And so you can make more to sell to the curious and/or give all family members as gifts
You may not need to bend the carrying thwart. Back in the day I had a 16 foot ABS Mad River canoe that had a straight carrying thwart made of white ash that was about 2.25 inches wide and about 7/8 inches thick. I took a length of 3/8 inch thick closed cell foam and wrapped it twice around the thwart for padding, held in place at each end with 1/8 inch nylon cord. It worked a treat on portages except for a slight tendency to rotate so the canoe slipped backwards. The canoe weighed about 75 pounds.
Depending on what you plan to use for the padding, you may find that it has enough body and flex to fit around your neck without having to shape to central member.
I agree with TriPolar. Nylon web strap. Two from side to side. Spaced far enough apart for your head to go through. Then two straps between them at shoulder width. Pad the shoulder ones. Four eyebolts in the gunwhales, hooks on the ends of the straps. Bonus is the rig is easy to ball up and stuff away.
A hint on making nylon straps.
It can be difficult to make sturdy loops in nylon strap. If looks are not important, one can use wire loom. It is a woven tube of nylon. I use it to make battery handle loops. I cut to the loop length I need with a bit extra. I soak the ends in glue that will harden solid. One end is slipped into the other. It is a tube, so one end can go in the other. I wrap with tape, then press in a vise till dry. One can just stack some heavy weight on top as well. Careful not to glue everything together. Then I have a sturdy loop.
I have not tried it. But I suspect one can make a sturdy loop at an end in the same way. With a buckle or such thing in the loop. Soak the loom material well through with hard glue, tape over and clamp.
Woven wire loom is available at car parts stores in various diameters.
Under tension, the loom will become thinner and longer. Very thin. So padding may be needed. Padding can be inserted before gluing. Say a pool noodle or water pipe insulating foam.
If using actual nylon strap. Grommets work well to attach it to itself for loop ends. Lots of cheap kits available.
Ratchet cargo straps may also work. No holes in canoe required. Two around the canoe, with a couple cross straps. Maybe salvage a couple backpack shoulder pads.
