I don’t post very often all though I follow the group very closely. The discussion about wing and round masts is interesting If both masts are free standing and rotating the wing if well designed will have if, head to wind, 75% less resistance then the round one. If the wing is not free to rotate a lot of degrees you’ll have a more challenging time in high winds. With the wing at a mooring or hanging on a sea anchor, if the boat travels back and forth 15 degrees either side of the wind direction the bridle ( 6 times the length of the boat) is not adjusted properly. Attaching an air direction fabric sock to the topping lift will keep the wing aligned straight into the wind. As far as performance a fixed mast will never keep up with a wing or point as high. A good choice with a wing rigged boat is to have it schooner rigged, if on a mooring or high winds at sea, if the wings are rotated in opposite directions the boat will sit head to the wind. I have experience with wings, never found them to be problematic.

A few years ago I had a number of deep conversations with a major carbon fiber mast supplier. We discussed wings compared to round masts (round is cheaper), (both masts free standing and rotating), if on the round mast you put vortex stimulators about 15 degrees either side of the centerline the performance may come close to a typical wing soft sail combination. We discussed and agreed the easiest way to make the vortex stimulators is simplify mask off the front of the mast so that 15 degrees either side of the mast’s centerline you have a ½ inch wide strip of very rough nonskid texture, the mast would still need to be free standing and be able to rotate, the mast while sailing would probably need to be over rotated about 7 t0 8 % degrees, that would need to be played with to see how much over rotation worked best.

The biggest mistake made for performance multihulls is the amount of camber built into the main sail, if your boat can do 2 times the true wind speed the main sail should be a board, no camber built in, a board has been proven many times to be absolutely  the fastest. The lowest batten should be the stiffest one, what worked best for me was to start with battens that I knew where to stiff, than  very slowly remove material until the boat didn’t go faster. I used the lowest batten and along with mast rotation and mast bend to control the overall shape of the main, if your boat cannot do 2 times the true wind speed, but say 1.5 times the true wind speed and has a rotating rig the most camber that should be built in is 1% and never more than 3%.

Even as far back as the mid-1970s a couple of us had catamarans that would sail 2 plus times the true wind speed. Each of us wound up with mains that were boards

Hope this was of some interest, Best Regards,

Ron