Looking at buying a Hanse 371

 

The sail has the same dimensions as the original, but the positive roach with vertical battens allows a bit more area. But really, it is the superior shape which gives the performance increase.

Grahame Shannon, Hanse 371 Tangleberryl

That post is so old, the sail has worn out and been replaced. It held the excellent shape to the end, but began to delaminate.

It was a so-called "string" sail where fibers are applied to a mylar substrate by a machine, following the strain contours. North 3DL uses a similar process.

I made the mistake of replacing it with a dacron sail to save some money. The new sail, from the same loft, looks fine, but does not have nearly as much power in light airs. Once there is 10 knots or more apparent, there is no difference. 

When the budget permits, I'll replace it again.