I haven't updated this thread in a bit, so I thought I would as the boat is pretty much a complete system now. The last pieces of the puzzle have just come together recently including a rudder, spray skirt for dirty weather and a proper racing paddle.
The rudder came together nicely. The rudder that I was interested in was pricey over $300 CDN, so I have been watching out for deals. A couple weeks ago, I happened across one, the only catch was it was attached to a used demo boat. Sweet, so I bought the boat which is a rather nice tandem kayak. So now, on week ends I can bring my son training with me on week ends, he seems happy to sit and play in the water, fish or whatever while I paddle, works for me. The rudder system is a fairly standard kayak rudder system. It uses cables lead to foot pedals, so you are steering with your feet because hands are busy with paddle. I think airplane rudders are the same deal, foot pedals control rudder. The rudder system is nylon, including the blade.
Spray skirt was an off the shelf item for my Kayak. For those not familiar with sea kayaks, they are fully decked boats, except for the cockpit which has a combing. You wear the spray skirt something like a skirt with suspenders and the hem attaches around the combing, creating a water tight seal, even when upside down, in theory self rescue is conducted by conducting a role with your paddle.
Possibly the most important detail was the paddle- the engine, along with the sail. I did a lot of research on this, books, paddling forums etc. At first I was looking at ergonomically designed bent shaft carbon fibre paddles. After chatting with some world record holders for distance paddling I decided not to go that way. I decided to go with a custom made western red cedar wood paddle. This type of paddle is known as a Greenland paddle the blades are quite narrow but long, basically shaped like airplane wings. On the power stroke you angle the paddle blades at about 30 degrees maybe, this creates lift on the forward edge of the paddle, much like a propeller or we as sailors are accustomed to our keels and sails doing. This effectively causes the boat to be both pushed through the water and pulled by the lift. And being custom made it is a perfect fit for me ergonomically. There are other bonuses too, but that's a big part of it.
Early on in the thread I roughly listed my specs. The final boat gets a lesser percentage of its power from the sail then I had originally envisioned and more power from its paddle. My testing so far seems to indicate that I should be able to meet my performance expectations. Maybe not 60 mile days, but consistent 45 mile days with higher potential on strong tail wind days. The boat doesn't seem to have much problem holding 5 knots on a run in a decent wind aft of the beam.
Here a quick look at her cruising along nicely with both the sail and paddle in play in light winds.