I had long batten parrels on Arion and got quite a bit of negative batten stagger until I fitted what I call Paul Fay fixed parrels on each batten, which went from the front end of a batten around the mast and back to the same point.  By adjusting their length, not only did I stop the battens going forward but I could induce positive batten stagger.  More friction for sure, but maybe no more than using short batten parrels.  Their primary advantage for me was being able to induce positive batten stagger.  Once I had these rigged, the sail furled like a dream.  I did have HK parrels as well, to help the set of the sail when hoisted, though once I had fitted Arne's throat hauling parrel, they did not do much work, except when the boat was pitching heavily into a head sea.

Branwen follows Chinese tradition: foremast raked forward about 6° and a vertical luff to the foresail, so that the lower battens and boom project further forward of the mast than the upper ones. The batten parrels are of moderate length. The sail always furls correctly, with postive batten stagger in spite of cambered panels.

Her mainmast is vertical, luff parallel to mast and the sail furls with negative stagger. In future,  I would always choose to rake all masts forward. Another happy result of forward rake is that the sail remains quiet when squared away before the wind in light airs and a sloppy sea.

Controlling batten stagger in a cambered panel sail.

Hasler and McLeod’s Practical Junk Rig, PJR shows the rules to get (just a little ) positive batten stagger, and thus trouble-free reefing of their standard, flat HM sails. David Tyler has with his PDF shown what corrections should be done to keep correct batten stagger in cambered (baggy) panel sails as well. This no doubt will work fine.

However, on my rather lo-AR sails, the boom rise would end up very high, so I have settled on another method:

·         I have standardised on a variation of HM-sails with 10° boom rise and 70° yard angle.

·         The 10° boom rise gives a sufficient clearance over the sprayhood or doghouse and lets me reef without adjusting the topping lifts.

·         The 70° yard brings the slingpoint of the halyard quite close to the mast. With over 15% sail balance the halyard will hardly pull the sail forward at all, even with the slingpoint moved a bit aft of the middle.

On the four boats, Johanna, Broremann, Edmond Dantes and Frøken Sørensen, this happens when reefing:
The sail moves forward (negative batten stagger) about 4% at the first reef. Then the halyard goes close to vertical and the half-short batten parrels prevents the sail from moving any further forward. The short batten parrels don’t add much to the friction, with the halyard not pulling the sail forward. (See Ingeborg’s sail with one reef, below.)
Still, the boom would protrude 4% from the reefed bundle and catch the sheets. This is why I cut off 4-5% of the sail and boom at the clew.

My present Ingeborg has proven to be a special case. Due to sloppy design work from my side, she initially turned out to have a bit too much weather helm with the sail fitted in ‘my normal’ position; with around 12% balance. I then shifted the sail forward until it was nearly at the aft end of the batten parrels (just by easing the standing Tack Parrel). The result is that the sail doesn’t move any more forward when reefing, so shortening the foot of that sail was actually not needed.

I find that this design method is easy to use, and produces trouble-free reefing. Moreover, one  can make sails with various camber ratios without redesigning the sailplan for each value of camber.

Hope this makes sense...

Arne

Ingeborg's sail with one reef.