Here is a shot of towing two AIs behind a Hunter 31 this summer.
We were towing while mostly under sail (some motoring, but not much), so speed never exceeded 5.5 - 6 kt. Speed at the time this was taken was about 5 - 5.5 kt. The Mirage drives were inserted, with one pedal bungied back, so the fins were held flat to hull. The daggerboards were both in, but were pivoted back. The rudders were flipped up onto the deck. As can be seen in the picture, the masts were in, and the amas retracted.
People who read my earlier posts might point out that I did not tie off as I described in the diagram I posted previously. I did not have a long enough line available to run one long line from the towing boat and tie each AI to that line. As both boats are always equipped with a 15-20 ft mooring line that I keep attached to the forward aka crossbar, I ran that line through the shackle I always keep on the bow padeye, and used that. The first boat is tied to the stern cleat on the Hunter, and the second boat is tied to the aft aka crossbar on the first boat. I did grab hold and pull on the tow line while at 5.5 kt, just to see how much tension was there. Not much at all, to be honest. While I'll still maintain that the method I diagrammed before is the "correct & proper" way to do it, in the conditions we were in that day, this method was more than strong enough. If you are towing in rougher conditions, or at higher speeds (still keep it reasonable, an AI is not a wakeboard), then the more robust connection diagrammed in the previous post would be recommended.
I watched the boats closely for a while as I was concerned that the line running across the stern deck of the first boat may snag on the flipped up rudder. In about four hours of sailing & towing, over almost every possible point of sail, and every possible angle to the waves, I never saw any tendency that this might be a problem. Conditions were pretty mild that day (7-10 kt winds with less than 1 ft waves), so that might still be something to keep an eye on though.
Next time we do this I will try to get a few more pictures. Maybe even some from another perspective. In the meantime, I hope this info helps.
Happy Sailing,
- Jim L