This article by a canoe tump enthusiast suggests a contoured centre yoke is a horrible innovation. His method requires the replacement of the "stinky" centre yoke with 2" diameter round aluminum tubing. Might work for him but not going to happen with my boat.
Contoured Yoke Protest
I also came across a recent article Portaging a heavy canoe with a Tump Line (PDF Format) from a staff member of Camp Nominingue in Quebec. This full colour, clearly written article outlines all the technical aspects although they tend to use canvas & cord based tumps. Interesting that their lashing method involves securing the tump cord 1.5 inches ahead of the actual centre thwart.
Camp Nominigue Setup
Since my leather tump is akin to the Northwest Woodsman's site, I've used his photos and accompanying YouTube video to learn the correct method of lashing it in. The video shows the method for a wanigan first and then for a canoe around the 3:50 mark. His canoe also has a contoured portage yoke just like mine.
NW Woodsman Tump Pics
However, one thing I never quite liked about the paddles being lashed in the claustrophobic space created by sandwiching your head between the blades. While re-reading the classic birchbark canoe text, The Building of a Chippewa Indian Birch-Bark Canoe by Robert E. Ritzenthaler I came across a paragraph (p. 96) describing one native way of using the tumpline.
It involved lashing the grip end of the paddles to the centre thwart with the blades pointed towards the bow. The position is such that the the shafts of the paddles are flared away at the yoke resulting in a much more open triangular space. The arms are wrapped around the shafts with the hands loosely griping the sides of the tumpline on the forehead. Here's the accompanying photo on pg. 95
One Native Tump Method
This last method appealed to me the most. With all tumplines however, trial and error to get it adjusted just right to work properly. While up north for a brief fall getaway, I got a chance to test out the setup. The tump was secured to the yoke with simple hitches but it took me about about 45 minutes of fiddling to finally find the right length. In the end, I figured out that for my boat and yoke, the best measure was when the centre of the tump's headpiece just touched the bottom of the hull when pressed down with my finger. This will make it much easier to attach/adjust in the future so as not to waste much time.
Laying out; Clove Hitch to Yoke; Re-adjusted length
The slack was used to tie in the grips of two paddles and a piece of 1/2" wide leather strip was used to secure the blades to the seat. In the end the setup was quite secure.
Grips lashed in; Blades secure; the final setup
Canoe tump portage
The results: I'm totally impressed with the use of tumpline. While my boat isn't a heavy beast to begin with, the tump and paddle setup really make for an seemingly lighter carry. I walked around the property with the canoe (including uphill) to a parking lot area drawing some funny looks from neighbours and while it wasn't an authentic bush portage, the tump carry did make a difference on the shoulders. From a safety standpoint, if I slightly shrugged my shoulders up and tilted my head back, the tump would slip off and roll backwards because of the way it was lashed in. A simple hand motion would swing the tump back into place onto the top of the head so it is relatively easy to get in and out if needed.
Especially significant was the ability to let go of the paddles and rest the arms while the tump & shoulders balanced the boat. Also, with the bulk of the weight borne by the tumpline, you only really need one hand to secure the boat while moving. To take the picture above, I set up a sawhorse in the driveway, placed the camera on it, set it on a 10 second delay and walked into position, all the while efforlessly balancing the canoe with the tumpline. It may have its critics, but for me, I can see the potential in this piece of gear.