David, when you say 'just the right spot' for the aft attachment of your short batten parrels, is this as shown in PJR, ie in line with the aft face of the mast, and a common parrel length based on the maximum mast girth?

The photos seem to show this as the sail's balance increases as the mast gets narrower, but did you just use the same parrel length on all battens and just let the sail find its own natural position, or are they different lengths for each batten?

The batten downhauls look from the photos to be attached at the same point as the aft parrel attachment, but the photo resolution isn't quite enough to be certain. Is this correct?

Bonjour Bertrand,

I think this rig is now fit to sail down the Pacific, and if all goes well, and Neptune smiles on me, I will be in New Zealand towards the end of the year. With luck, we will be able to meet in New Zealand and talk about wing sail battens!

I forgot to say in my last post that the downwind leg from Silva Bay to Blubber Bay, Texada, was in a strengthening wind that needed four reefs by the end. I was just easing the halyard and taking in the downhaul and the sheets. No problem. No difficulty in lowering the sail, no breakages.

But there was a little problem when gybing with four reefs. I think what happens is this:

Suppose you're on starboard tack; the hinges are articulated out to port. Then you decide to gybe. If it's windy and you're deep-reefed, the after ends of the reefed battens tend to lift up high during the gybe. Because the sailcloth is slack, the hinge wants to drop under its own weight, and this causes the batten to rotate on its axis, to allow this to happen (this is because there is no vertical articulation in these lower battens). So the starboard side of the batten is now on top. Then, after the gybe is completed onto port tack, the wind in the sail pushes the hinge, which is still hanging low, to starboard. This completes the rotation of the batten through 180 degrees, into a stable, inverted state. It doesn't cause breakages, unlike the with the wing sail battens, and it will correct itself when the reefs are shaken out.

What's the solution? Ideally, the vertical angle should equal the horizontal angle. Then there is no tendency to seek any rotated position. Not more, or you get the problem I had last year, where the wingsail battens were stable in an 'on-edge' position. Not much less, and certainly not zero, or the battens can be stable in an upside down position. 

Yes, but where to put the mast......  Each of the rigs would prefer a different position, and I have omitted the Split Junk Rig from the list as this is the one sail that David has yet to fit on his boat.

If David hadn't sailed into my corner of the world I could have built a cambered panel junk and just been happy about it.  However, the wingsail is irresistible in so many ways (ignoring cost, time and keeping it from breaking).

Yes Arne, I think we were talking across purposes, which was not helped by my misusing the word stall in my last post.  I see your point about the leach telltales being useful for detecting oversheeting, but in my original post I was trying to describe the differences in the sails as one as trying to sail as close to the wind as possible.  In this regard, with a traditional sail it is easier to detect when you have pinched too far and the sail begins to luff.  Given my limited experience, this transition seems to be more abrupt with a traditional or cambered panel sail and is easier to detect because the single layer of sailcloth luffs, which is easy to see, and the boat shows a distinct transition as it loses drive.  However, as you pinch with a wingsail the loss of lift or drive seemed more gradual and the two layers of sailcloth obscure any luffing of the leeside cloth.  As you said, leach telltales aren't much help in this case (but are still useful in detecting stall or over sheeting).

Mark, I think the fact that the wingsail is happier over a wider range of angle of attack (AoA) also changes the behaviour of the sail in a way that gives it a different feel.  The wingsail produces useful lift over a wider range of AoA, which is good to keep the boat moving in variable wind and waves, but also makes detecting when you've got it sheeted perfectly more difficult ascertain (happily it probably also makes it less important to sheet it perfectly).  Even in conditions of steady wind and little waves the wingsail should have a better lift to drag ratio.

Sorry, I didn't mean to hijack the thread into a wingsail discussion.  My main point was that the new hinged sail is powerful and seems to be working well.  The cambered panel fantail sail was also good.  All three sails work and have some interesting differences.