Hi Barry and Meps. I have had similar problems with my cambered HM sail. The throat hauling parrel, as set up by Arne, significantly resolved my problems with the set of the sail. It is a variation of the standard luff hauling parrel as shown in PJR. In my experience a luff hauling parrel is essential for this rig, and Arne's system. where the parrel goes from the forward end of the yard around the mast to the front of the third batten down then straight to the deck is the most effective way of getting the sail to set properly. I have no diagonal creases now, even though I am currently sailing with only one HK parrel rigged in the intermediate panel. I also rigged my yard hauling parrel the way Paul Fay suggests, taking the tail to the front of the yard before bringing it down to the deck. This allows it work in tandem with the throat hauling parrel. When rigged in the standard PJR way, there was a lot more tension on the throat parrel as they were pulling against each other. I have also fitted Paul Fay standing luff parrels, with plastic hose over them where they go around the mast, on all the parallel battens, making each one a bit shorter as you go up. That forces each batten a little bit further aft as they stack and I now have perfect positive stagger when I furl. I also lashed these Paul Fay parrels, where they loop around the mast, to the battens, so they act a bit like short batten parrels. I have only hoisted the sail at the dock since but it seems to work perfectly. An added advantage is that it should reduce the amount by which the sail hangs away from the mast, though I don't see this as a significant problem. I may eventually remove my long fixed batten parrels on these battens. I attached my long fixed parrels (and HK parrels) to the battens with rolling hitches, not wanting to drill holes for saddles in the middle of the aluminium battens, in case flexing caused cracking and breakage, but they have a tendency to creep. I recently left a long tail on the rolling hitches on the two upper fixed batten parrels and seized them to the batten. So far they have stayed put.
I find these cambered sails a bit of a pain but the performance is definitely superior to a flat sail. Nonetheless, in conversation recently with Chris Bray and his partner Jess, who recently sailed through the NW Passage on Teleport, Chris stated that he was perfectly happy with the performance of his flat sail for offshore cruising and would not trade its rugged simplicity for a bit more performance, and I tend to agree with him. In my opinion, these cambered sails are best suited to performance oriented inshore sailing. That's what I am doing at the moment so I am happy enough but I may go back to a flat sail if I go offshore again.