I can create drawings of all the intersections of the stringers and frames. My plan is to then simply print them out on paper. Glue stick them into the frame timbers and cut and chisel them out. The plywood I will cut on my large CNC router.

I want to keep track of time spent on this project so far, I would take a rough guess at this point of around 20 hours of CAD, and another 10 hours of contacting suppliers, researching etc.

I plan to have a small electric auxiliary (a brushless trolling motor). With a 24v 100ah LifePo4 battery. Should give 3-4 hours of ~4 knots, in near silence.

It has taken a bit of time, but I have managed to find the manufacturer of these very tidy self-contained trolling motors. Without being on an outboard style tiller. I hope these will be a great option for small homebuilt boats. So after trialling one on Swiftsure I will probably start importing them. As I can't find a good equivalent for this anywhere from Western suppliers, at any sort of reasonable price. This will cost around the price of a name brand 3hp outboard. With no ongoing fuel costs, simple anodes and seals to replace. I will put a small solar panel and charge controller on the trailer to top off the battery between weekend sails. Or take the battery home to charge.