Carl,

All agreed.

I've been discussing the alternatives for my sails with the (reputedly) best multihull sailmkers in Brazil, Cognac/Elvstrom and they sent me one of their published articles where they (basically) say that:

a) "Rigid" sails (3DL, reinforced film, etc.) have one important shortcoming - since they are not flexible, they can only be relatively more efficient in the tight wind speed range they were designed for.

b) "Flexible" sails (Dacron and others), if properly designed and cut, have a wider speed range where they are efficient, making better all-around sails. They can be more efficient then rigid sails, depending on the frequency and amplitude of the pressure changes in the specific day.

c) Sailmakers prefer rigid sails because more sails are needed in a complete inventory, with obvious $$$ consequences.

d) As a consequence, sailmakers generaly downplay the merits of flexible sails - which, by the way, are more difficult to design and cut.

Also, they claim that rigid sails do not maintain the design shape they are supposed to. Their practical metaphor was: when you cut an avocado in two and eat the pulp of both sides, the remaining half-shells do not match anymore only because the pulp (mold) was removed. A similar thing happens with rigid sales, although obviously in a lower scale. After they leave the mold, they do not hold their shape for long.

Cognac-Elvstrom has access to cheaper labour costs in Brazil, so their flexible sails are relatively inexpensive (and reputedly excelent to all but grand-prix racing). Since they also do rigid sails, it is easier for them not to have the same bias.

However, although all this seems logic and reasonable, I am just summarizing their opinion and am far from being an expert.

Cheers,