I wonder why that is. Allowed to feather into the wind and with a symmetrical profile, theoretically (as Chris says) it shouldn't generate any lift
. Maybe the mast on that boat has too much mass and won't rotate quickly enough on a shift. Chris's are just lightweight carbon foils wrapped around a stationary mast. They should spin easier than a traditional rotating mast.
One thing you notice is missing from Chris's descriptions is any talk of speed. If I were buying
one, I'd wonder about how much power those wings actually make. He seems to already have tweaked it for more power by lengthening the chord and shortening the flap. Surprising that none of the owners of the 3 in build have a blog or anything.