I know Tag did not intend this, but use caution clicking on the first link from Tag - as soon as I get to the Sunfish pics, I am getting popups to install an antivirus software, and then get a McAfee warning. The Sag Harbor Express link is fine.
"Changing the sail geometry from the Sunfish’s traditional shape, Sandell and Farrar’s design shortened the foot (bottom edge) by 18 inches and added sail area aloft to catch higher and cleaner breeze. Less sail area in the stern of the boat along the foot reduces weather helm. With the wider roach, Sandell sought to move the center of effort forward so the boat wouldn’t round up so much."