Outhaul

{{Short description|Control line found on sailboats}}

File:US Yachts US 22 sailboat Vesper outhaul 1133.jpg sailboat. This design uses a braided steel cable, with a swaged thimble and clevis to attach to the sail clew grommet.]]

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.{{cite book |last= Donaldson|first=Sven |title= Basic Sailing Skills |date=1994 |location=Gloucester, Ontario |publisher= Canadian Yachting Association|page= 117|isbn=0-920232-17-5}}{{cite book |last= Donaldson|first=Sven|date= 1992 |title= Advanced Sailing Skills |location=Gloucester, Ontario |publisher= Canadian Yachting Association|page= 130|isbn=0-920232-19-1}}

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.{{cite book |last=Smith |first=Lawrie |date=1985 |title=Tuning Your Dinghy |location=West Sussex |publisher=Fernhurst Books |page=51 |isbn=0-906754-18-6}}

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.{{cite book |last=Bethwaite |first=Frank |author-link=Frank Bethwaite |date=1993 |title= High Performance Sailing |url=https://archive.org/details/highperformances00fran|url-access=registration |location= Camden, Maine|publisher=International Marine |page=[https://archive.org/details/highperformances00fran/page/209 209] and 291 |isbn=0-87742-419-5}}