Anonymous wrote:
I guess I play in the cambered sail league, surprise, surprise, and for much of the same reasons that David Ty. and Paul Th. mention. As for how much camber is right, I don’t know. On my boats, I have settled on 8% camber in the lower horizontal panels. Those 8% camber is measured mid between the battens, so over much of the panel, this max camber is less than 8%. Anyway, I use telltales at the leech to monitor (and ensure) attached airflow along the leeside of the sail. Despite the obstacles along both sides, the airflow seems to stay attached quite well, until I over-sheet the sail.
The top panel of Ingeborg’s sail has only 44mm round along its yard and top batten (B = 4.90m). Even so, the airflow appears to stay attached, and there is no flogging or shivering along the luff or leech.
This summer I can celebrate 30-year anniversary for my first fully cambered panel sail, made for my Malena. Pure bliss.
Cheers, Arne
PS: I have never seen any warnings against cambered sails for offshore gaff rigs...

Malena in 1994
Arne, when this photo appeared in my PBO magazine 30 years ago, I decided that any junk sailing under my ownership would have sails with cambered panels. Since then, I have rigged two boats with cambered panels, one of which has crossed the Atlantic and successfully returned. I continue to bow before you, my sailmaking guru.
Kurt Jon Ulmer is coming close to seducing me away with his talk of flat sails, with a form of camber supplied by twist. I like his elegant sail designs in which there are no heavy loads on any part of the rig. Aboard my 32ft schooner, I sometimes peered through the alloy yard and could not see daylight at the other end - the concentrated forces at the peak and the throat were bending that spar, making me wonder what I would do if, like Sebastian Hentschel's 'Peregrine's, it would break.
I am also thinking about the Kingfisher 26 'Chopsticks', where a cambered sail was made to replace the flat one and the owner now discovered that she heeled much more than before under the flat sail and became almost unmanageable because of heavy weather helm.
Shirley Carter is now in the Indian Ocean, ⅔ of the way around the world in her ancient Vertue, 'Speedwell of Hong Kong'. Some time ago, she converted her Vincent Reddish style rig, giving it cambered panels in hopes of improved performance to windward. From reading Shirley's excellent blog, I discovered that she was dissatisfied with the new sail, perhaps largely for aesthetic reasons, and went back to her flat sail.
These thoughts are preoccupying me at the moment, since I have just bought another boat, 'Rosalina', a Rival 32. I think she might suit me in all respects except for her one great defect - she is rigged as a Bermudian sloop. I don't know if any other Rivals have been given junk rigs, but I have started chewing pencils and wondering how she would look as a junk, and wondering where I could get a mast for her.
Asmat