Speaking of new concepts, Calvert went with a new design last year and did it with Dacron. Awesome sail that pretty much out points all the other sails and goes a bit faster. Seems Dacron is easier to alter the shape for varying conditions. And unlike the exotic materials it is hard to oversheet the sail. With exotics the leach will hook, while with the Dacron, it falls off a bit, thus allowing a higher angle to the wind.