An outhaul is a control line found on a sailboat. It is an element of the running rigging, used to attach the mainsail clew to the boom and tensions the foot of the sail. It commonly uses a block at the boom end and a cleat on the boom, closer to the mast, to secure the line.[1][2]

The outhaul on a US Yachts US 22 sailboat. This design uses a braided steel cable, with a swaged thimble and clevis to attach to the sail clew grommet.

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 a racing sailboat, should be knotted and the boom marked with the settings for different wind speeds.[4]


  1. ^ Donaldson, Sven (1994). Basic Sailing Skills. Gloucester, Ontario: Canadian Yachting Association. p. 117. ISBN 0-920232-17-5.
  2. ^ Donaldson, Sven (1992). Advanced Sailing Skills. Gloucester, Ontario: Canadian Yachting Association. p. 130. ISBN 0-920232-19-1.
  3. ^ Smith, Lawrie (1985). Tuning Your Dinghy. West Sussex: Fernhurst Books. p. 51. ISBN 0-906754-18-6.
  4. ^ Bethwaite, Frank (1993). High Performance Sailing. Camden, Maine: International Marine. p. 209 and 291. ISBN 0-87742-419-5.