Having owned many sloops, and most recently a Nonsuch, I have little use for jibs. Nor, I should point out, do the world's fastest boats, other than as a light wind auxiliary sail. I also really appreciated the simplicity of the unstayed rig on Nonsuch and Freedom yachts. The unstayed carbon rig is lighter and has a lower center of gravity than a stayed rig. There is at least an order of magnitude fewer points of failure: if the mast tube, heal bearing, and partners bearing are intact, the rig will stand. The reliability record of carbon unstayed rigs is all but absolute.

The Nonsuch has a wishbone, this has some problems when applied to a large square head sail. I believe a large square head is key to performance on a una rig. Almost all of the tension in the sail is between head and clew (I can unload the tack shackle by hand even when powered up on a beat). A wishbone would have to be at an extreme angle or be rigged with a vang (Team Phillips did the latter) to control the twist on the square head. So 'Anomaly' carries a conventional boom. The sail maker calculated 4000 lbs download on the clew which requires a powerful vang. A fractional sloop requires lots of twist in the mainsail due to the twisted downwash from the jib. A large cat rig needs very little twist - 3 or 4 degrees is plenty. (A small dinghy cat rig wants considerably more, because it operates low in the wind gradient). I wanted to keep the boom low enough to reach the sail, remembering that the stack height of the sail slides adds over 4 feet. If the hydraulic vang were under the boom, the angle of pull is poor and we would need a 20 ton cylinder. This led to the inverted vang. It has a much better angle and the boom can be as low as you like. However you need two cylinders, one on each side of the sail, and the attachments at the mast have to accommodate sail trim. This is much easier if the mast rotates.

The rotating mast started as a performance feature, however I searched the world for hard data and there is none indicating a noticeable performance increase from rotating the mast. There is some scale wind tunnel tests, but they don't represent the dimensions we are using (mast D vs. sail chord). There might be an advantage with very careful design and a shaped mast section, but a shaped mast section causes many problems on a cruising boat: in produces lift all the time, even when you don't want it. However among those with rotating mast rigs the consensus was universal that the operational considerations alone made it worthwhile. The sail track is always inline with the sail, solving a lot of problems. It also solves the inverted vang connection problem.

My experience with the una rig on the Nonsuch revealed a few problems: With just one sail, you cannot control the boat when it is stopped. You cannot heave to. All the windage is forward and so the boat sails at anchor more so than a sloop. I added the small mizzen to solve these problems, and so it has. The mainsail is 960 sq ft, the mizzen is 215. The boat heaves to nicely on the mizzen alone, is rock steady at anchor with the whole or reefed mizzen set. I can stop it, turn it, back down with complete control under sail by backing the mizzen. The mizzen boom is sheeted to the quarters with two independent sheet tackles to make backing it easy standing at the helm. It has a conventional boom and hydraulic vang. The mizzen mast is spaced far enough from the main (the masts are stepped 35' apart on a 45' boat) that it does not suffer as a normal mizzen would. We do not need to sheet it to the centerline upwind, and it adds about 0.3 knots drive. I can even sail upwind on mizzen alone after a fashion. It makes a convenient mount for radar and wind instruments - neither can be on the mainmast because it rotates.

In retrospect, I wish I had made both booms lower still. It is a stretch for me (6' 4") to deal with the sails. Other than that the changes I would make are minor details. We have not seen many other boats to sail against to date, performance seems to be good but there is nothing like falling in on a race course to see how you really do. Maybe in LIS.

You were going to be in Boston? 'Anomaly' currently is moored in Salem, will be heading south to LIS around last week of August. I still want a ride on your Dragonfly.