Anouthaul is a control line found on asailboat. It is an element of therunning rigging, used to attach themainsailclew to theboom and tensions thefoot of the sail. It commonly uses ablock at the boom end and acleat on the boom, closer to the mast, to secure the line.[1][2]
The outhaul is loosened to provide a fuller camber or tightened to give the sail foot a flatter camber. Depending on the wind, this will increase or decrease boat speed.[3]
Sailboat designer and sailing theorist,Frank Bethwaite, recommended that the outhaul, along with the other sail controls on aracing sailboat, should be knotted and the boom marked with the settings for different wind speeds.[4]