Seems to have gone AWOL. I have stored a copy here.

Chris

For some reason, which I have forgotten now, back in January I drew up a modified Fantail sail. It has a less aggressive yard angle, which should make it easier to set, with less loadings on the LHP and on the cloth in the throat area. It also has a straight ove sail, even though those stresses would be less than in Fantail's current sail. I'd be looking around for a polyester cloth with as little filler as possible.

Bryan, please can you send me the .dxf file for your latest sail design? I may then be better able to understand the changes you've made to my revised fantail planform, and suggest improvements.

• I don't know what I'm doing. This represents a synthesis of my best guess and suggestions from two Davids, Arne, Paul and Annie.
• Because I'm lazy and tight fisted, the sail is based around Fantail's existing yard and battens.
• I figure that the short yard/truncated top panel will work fine, with the proviso that there is no camber above the top sheeted batten. This should allow the downward component of the sheet load on that batten to be transferred to yard via the upper panels rather than the leech alone, and hopefully addresses Arne's concerns on that score.
• The sail is fanned because it allows greater support of the upper panels than an Arne/HM shape does when the aspect ratio is of necessity so low. This may not be a problem at all, but as a novice I feel more comfortable with more batten support. Besides, and just as importantly, it wouldn't be Fantail without a fanned sail.
• The original Fantail sail will not tolerate more than a whisker over 6 degrees of camber before developing negative stagger. This may not be a problem, as some have suggested, but I'm wary because of the steep sheeting angle that occurs of necessity in Fantail's case; also, she furls perfectly now and why risk spoiling a good thing? The rather sharp boom rise in the planform above allows for any amount of camber.
• The leech should be less conducive to fouling sheetlets during gybes than Fantail's current sail, I hope.
• The new shape has one less batten than the original (a good thing, I think), and is a tiny amount down on area (not so good, I think).
• At some level of camber it seems that running lazyjacks will likely be beneficial. As I'm too lazy for that, I'll ponder how much camber can be put in before this matters.
• The yard angle is dropped to 65 degrees to ease the throat load of the sail, which has been an issue on the current sail.
• As the sail fans, the camber shape will follow, i.e. the point of maximum camber will be further aft on the upper batten compared to the lower in each panel in order to prevent the max camber point being angled across the 'sloping' panels.
• I'm mindful too of Annie's comment that there's only so much one can expect in the way of performance of a small boat on a bouncy sea. I'm still pondering the question of how much camber, and I certainly don't want to lose any of Fantail's easy-going nature in some wild-eyed quest for more drive.