Lidgard Sails A1 Gennakers are performance light air sails. They often have a tighter luff that enables the sail to stay set in light breeze and rolling swells. Constructed from .5 ounce nylon cloth to keep the sail light and easily flown. An A1 Gennaker has reduced shoulders and is usually a flatter sail to reduce stalled wind in the Gennaker and create wind flow.