||WOW! Awesome fun!
Hobie doesn't really advertise that the sail kit goes to windward, but it does.
I was getting the i12s, with the inflatable version of the sailkit (has stays, instead of a free-standing mast), to occasionally point almost 40 degrees into the apparent wind, but that was pinching, and losing speed, and making some considerable leeway. Looking at the gps tracks, I was able to get 55 degrees (actual gps track) off the wind, pretty consistently, and that was on my first time out. I'm sure I will get better at trimming the sail. 50 degrees may not be out of the question.
But even if you only got 60 degrees, doing 2 mph with sail-power only, and had to get directly upwind, that means you are getting 1 mph toward your upwind goal, with zero effort exerted. As the apparent wind got close to 10 mph I was getting around 3 mph. That's somewhere between 1.5-2.0 mph made good to windward, with no effort.
When I peddled, I could get significantly closer to the wind. With the sail sheeted in tight, and with me peddling hard, I could get between 20-30 degrees apparent, with the sail still helping.
I have the turbo fins, and the sailing rudder. I've heard you need both, and I believe it. Aside from a lot of leeway, which would only be worse with the smaller fins, the setup felt good. With the original fins, it felt like riding a mountain bike around in first gear. The turbo fins provide a much better feel to the pedals. If anything, they might still be a little underpowered--but at least they still fit in the mirage drive bag.
The stays stretch a lot. Some owners have replaced the nylon cord with Spectra line, which doesn't stretch nearly as much as nylon. The stretching didn't seem to be a problem in the light winds today. Occasionally, as the wind got higher, it was nice that the sail "heeled" (but not the boat), and depowered itself a little. Originally, I had planned to get some spectra stays, but after today, I don't really see any point on the side stays. May still make sense on the headstay, since, as it stretches backwards, it may give more weather helm in strong winds, and cause the kayak to round up to the wind.
The leeward sidestay sags, even with true wind of around 5 mph, but it wasn't a problem. On downwind legs, it was actually nice, because it let the sail keep its shape better, as it went forward into the sagging stay, and let me sail a deeper angle. I was getting about the same speed downwind, as upwind, which was a pleasant surprise. For a while the wind held steady around 6 mph, for an upwind apparent speed of about 8 mph, and a downwind apparent speed of about 4mph, with boatspeed right around 2 mph both ways. Not speedy, but with you being right on the water, it almost felt fast.
With the sail and peddling, I was able to keep the boat between 4-5 mph for brief stretches (and I'm terribly out of shape, so a fit person could easily do better), and that felt VERY FAST! Lot's of water noise, and occasional splashes over the side hitting your feet.
I was surprised at how easily it sailed. I was worried that holding the sheet, without any cleats would be tiresome. But it didn't take much effort, with the way I rigged it. Even when I was fussing with the iPhone, or wind meter, or getting lunch out of the dry bag, it held course reasonable well, for a while, on it's own. If I could figure out a way to keep the "tiller" (which occasionally drifted a little) in place, it would probably do even better.
I ran the mainsheet to the triangle ring back by the rudder, as instructed. The rear carry handle is on there, but I just moved it to the side, and it didn't cause any problems. With it run from the clew of the sail to that back ring, and then forward, the sail and sheet cleared my head nicely, even with a wide brimmed hat on my head.
From the back ring, I ran the sheet forward, and under the fwd right strap that attaches the seat to the kayak floor. In winds under 5mph, this seemed to "cleat" it well enough.
Later I tied a bowline at the end of the mainsheet to put over my foot. As the apparent wind got up around 8mph, this worked well for hands-free fine tuning of the sail--especially on close reaches. Downwind, I couldn't get my leg and foot back far enough, so I had to take it off my toe. But as the apparent wind went from 8 mph to 4 mph on the downwind runs, the mainsheet didn't really need cleating.
Video at http://www.youtube.com/watch?v=rqsO4ZjU1-s