Which sail shape has more power?

• A. Flatter sails
• B. Fuller sails
• C. Centered sails
• D. Balanced sails

Answer: (A)

Power comes from the sail acting like a wing: it generates lift, and the forward thrust you feel depends on how efficiently that lift is produced and how much drag the sail adds. A flatter sail shape helps the airflow stay attached to the sail and reduces unnecessary drag, so the lift acts more effectively in the forward direction. In practical terms, this means more forward propulsion for a given wind while you trim and steer, especially as wind stays moderate to strong. Fuller sails, while they have more area and can catch more wind in very light air, tend to incur more drag and are more prone to flow separation, which reduces the forward thrust they provide. Shapes that emphasize center or balance relate more to helm feel and steering ease than to increasing forward power, so they don’t inherently deliver more propulsion.