I have been experimenting a bit with a strap yoke on my solo canoe. It was discussed on another forum by Mike McCrea so I take no credit for it. It seems to work well for short distances. haven't tried it on anything over 100 yards. I did discover something accidentally that I like about it. It is rigged a little forward of my fixed seat. One day I was rigging the foot brace bar and I sat in the canoe to get the bar adjusted without unbuckling the strap. It was a lot more comfortable having a bit of support under my thighs from the strap than just sitting on the seat alone. I haven't figured out a downside to just leaving it rigged all the time. This may not work with all seats. It depends on the seat height and the slack in the strap but in my canoe it works for me.
Dave
Dave