Hey, guys. I'm kinda back. A guy at work has been wanting to learn boat building so I built a SoF canoe with him, a 15.5' version of my Yaquina design. I don't like how it came out, so I re-examined the design, and now I've made it better.
To my mind, this is the first "extendable" SoF design. Using the same frame pattern, you can get an 11.5' solo canoe (the Yaquina), 15.5' tandem canoe (Willamette), and an 18.5' tandem + canoe (Columbia.)
It's dead boring: totally symmetrical, completely flat (no rocker) and completely utilitarian. Ugliest canoe you'll use every time you get on the water.
The frame/stem pattern fits on a piece of plywood 48 x 32 so you can build 3 boats out of one sheet of ply.
It needs (1) keel 3/4 x 1 1/2, (4) stringers ~ 3/4 x 3/4, and 4 gunnels ~3/8 x 1 1/2, you can get the breasthooks and floorboards for the Yaquina and Willamette from a sheet of 1/4" ply. The Columbia requires 1 sheet plus another piece ~ 24 x 36.
There's a guy in Virginia who will start building a Columbia class soon. I've sent him the specs. I'll be developing a Build Guild from his experiences.
We'll be building another Willamette class canoe once we get finished with restoring a 16' fiberglass canoe we've been given. I'll let you know how it goes.