Hello Rick,
Yes, the more I've thought about this I realize that the channel isn't wide enough as is. Removing the back lip and using a washer to give space should do the trick as you have suggested.
Regarding the sail canoe...
A very long time ago when I was a little boy my brother and I saw a sail canoe on Ojibwe Lake in northeastern Minnesota where our family had a summer cabin. We had a 17' Grumman canoe my father had purchased just after the war when Grumman retooled from making aircraft and started making watercraft. I believe ours was from 1947. Anyway the canoe we saw sailing on our lake had an optional sail rig and we thought that was the cat's meow. I never forgot it and always wanted one.
Two summer's ago my brother and I took an overnight canoe trip down the Kawishiwi River near Ely, Minnesota as a kind of farewell to youth adventure. I was 70 at the time and Jon was 73. My big sister (then 80) and her boyfriend (76) had a second canoe. She had not been on this beautiful river for over 50 years so it was a meaningful experience for her. A lasting memory is of my sister and her boyfriend capsizing in a rapids and of seeing her floating past me down rapids feet first... her looking over at me with a radiant smile and calling out "how many girls get to do this!" What a woman.
In yet another rapids we had ho business shooting, my brother and I demolished a 15' Grumman and limped to the end of our trip in a crumpled and badly leaking canoe. Last summer I got to looking at that wreck and wondering what I should do with it. It was then that I remembered the sail canoe from over 65 years before. An advertisement in the local weekly paper led me to the purchase of a Grumman sail conversion kit from 1953 which had been stored in the loft of a warehouse for decades. Last summer there was no bike camp with Steve laid up with a bum knee, so it became the summer of the sail canoe. Great fun learning how not to sail and after capsizing and then doing research on how not to I designed and fabricated outriggers which have worked beautifully. A second canoe (not Grumman) came into my life at summer's end and a second mast and sail originally made by Grumman. With experience from the first canoe a 17 foot Grumman double ender which I bought scrapping the idea of using the bent up 15 footer from the rapids when I learned that the sail was too big at 66 square feet for a 15 foot canoe. Anyway this second aluminum canoe is a 15 1/2' square stern and using the hardware from the first canoe as a model I figured I could make the hardware (including lee boards and rudder) for this second one. A project! Yay! Indian summer stretched into a long fall and I got much further along than I had anticipated, making the mast step and thwart, outriggers and thwart for carrying them, rudder and rudder control and the rest of the bits and pieces needed to finish it off. Most of the hull has been polished with oxidized dull aluminum removed and a shiny surface revealed. It looks really good for what it is... a beat up old canoe in a second incarnation. It is nearly done and will be once spring thaw is done arm wrestling old man winter, who in my neck of the woods is a tough old fart. Something like me, actually. The square stern will remain on a canoe trailer I remade from two boat trailers and will be parked outside my apartment in town, ready for an excursion on one of many lakes in the immediate area, one of which borders my town. The double ender will be moored at Eagles Nest Lake 12 miles from town where I have a vintage aircraft trailer on my brother's property and where I spend most of the summer (bike camp). Summer fun. It looks like Steve will be well enough to make the excursion from B.C. to bike camp, so part of my summer will be on the water paddling and sailing and fishing and some of it will be making sparks with the welder with Fasteddie. Life is gooood! I'll post some photos in the tavern section once summer is here. Thanks for letting me bend your ear.
SB