Yakima bars are 3/4" steel pipe with plastic coating on it.
Whazoo's canoe has ends curved up, so flipped canoe goes on the top of AC.
Looks like it adds `18' of height, so not possible for most of solid walls TC.
My canoe is flatter, so canoe "hugs" the AC, while adding maybe 4-6" to the height.
Also being flatter- all it takes is 2 bars to stay solid.
Weight is important. My first canoe was 80lb and even I could easy carry 150 lb at the time - pulling 80 lb sucker on the roof was quite a challenge.
So I got 45 lb Wenonah and that thing makes everything much easier.