I finally got Blue Moon out for my first sail with the new, cambered junk sail built for me by Paul Thompson using Arne's barrel-cut design. The Weathermax 80 sail is 23 sq m. Paul wanted to use Odyssey 111, but based on my experience with that material on Arion's first sail, I will never ship with that product again. Paul cautioned me that Weathermax 80 might be too heavy for such a small sail, and perhaps he is right because in 5-10 knots of breeze the lower panels only inflate about 90%, leaving slight horizontal folds along the battens. But the panels assume a beautiful cambered shape and I don't give a damn about a few wrinkles. You only have to look at my clothes!
The wind was very light at first, about 5 knots, but the panels still assumed a good shape and the boat ghosted along at about 1.5 knots over a smooth sea. Later the wind picked up to about 10 knots and we were close reaching at about 4 knots. Close-hauled, the speed dropped to 3 knots. This was very pleasing, as the sail area is on the conservative side. The designed sail area for the bermudian rig is 27 sq m, but I could not fit that onto the existing mast. The helm balance seemed fine and the Windpilot self-steering gear operated perfectly, though I could use a bigger rudder for broad reaching. In operation, I'd say the amount of sail forward of the mast is no more than 20%, maybe a bit less.
It is interesting that the sail behaves very much like a flat-cut sail, unlike my experience with Arion's cambered sail. it has textbook positive batten stagger and does not require Hong Kong parrels. I just have one luff-hauling parrel. I suspect the weight of the material has something to do with this, but mostly I believe it is a result of the very heavy tabling at luff and leach that Paul uses. The leach tabling is about 300mm wide with five rows of vertical stitching, while the luff tabling is 250mm wide with four rows. The tabling makes each panel behave as if it is flat-cut. Arion's Odyssey sail had a 50mm webbing strap up the leach and very little in the way of reinforcing at the luff, so that they were both very soft, and stretched easily. That sail had outrageous negative batten stagger until I fitted fixed 'Paul Fay style' luff parrels on each batten. But I don't really know, I am no engineer. Monkey see monkey do is my modus operandi. All I know is that this new cambered sail works.
I am delighted with the result. I stand my my opinion that cambered sails don't have as much to offer heavy, beamy hulls when hard on the wind in the open sea. After all, Arion originally had a towering bermudian sloop rig with fully-battened mainsail, and it still sailed very sedately to windward when the sea was up. I am sure, though, the camber helped drive the boat better when reaching. I chose to go back to the simplicity of a flat-cut sail when I replaced Arion's cambered sail, though that was largely because I could not find a local sailmaker who understood the methodology, and I decided it would be good enough. It was, but Blue Moon's cambered sail works so well that I'd be happy enough to choose such a sail whatever the boat.
Thanks Paul for a great sail and your very generous discount.
Here are a couple of photos of the new sail. You can see the details of Paul's meticulous workmanship and the heavy leach tabling. The photos are not brilliant as the sun was always on the wrong side of the sail and it was hard to get far enough away on such a small deck! You can click on the photos to view full size.


PS: I meant to say that Blue Moon has a performance-oriented hull, based on the English ocean racers of the 1950s. Designed by John Illingworth, and probably with hull lines influenced by Angus Primrose, the Top Hat 25 was created for the Junior Offshore Group racing fleet in the early 1960s. I knew it would respond well to a high performance sail. The boat's performance potential and sail area is similar to Jester's, which leads me back to a thought I have often had. If Jester had had a larger, cambered sail in 1960, it may well have won the inaugural OSTAR. As it was, Blondie came in only 8 days after Chichester, who was sailling the 12m bermudian-rigged Gypsy Moth 111. If Blue Moon had a 30 sq m cambered junk sail, it would be a rocketship!