The FRC-B Mainsail for the Atlantic has a radial clew which enables the sail to hold its shape better in all wind conditions. The radial foot helps the lower part of the main to stay flat when you tension the outhaul. The radial head helps carry the shape all the way to the head and keeps the draft from moving aft as the sail is loaded in heavy air. The improved panel design will improve the sail's durability. The sail will stay faster, longer.