Outhaul
Encyclopedia
An outhaul is a line which is part of the running rigging
of a sailboat
, used to extend a sail
and control the shape of the curve of the foot of the sail. It runs from the clew (the back corner of the sail) to the end of the boom
. The line is pulled taut to the appropriate tension
to provide the desired shape to the foot and then secured to a cleat
on the boom.
The details vary, but the two most common methods are:
The outhaul, besides simply holding the sail out, is an effective sail shape control. Tightening or slackening the outhaul can flatten or fill out the sail, shift the draft
forward or aft
, change leech and foot tension, and increase or decrease camber
.
Running rigging
Running rigging is the term for the rigging of a sailing vessel that is used for raising, lowering and controlling the sails - as opposed to the standing rigging, which supports the mast and other spars....
of a sailboat
Sailboat
A sailboat or sailing boat is a boat propelled partly or entirely by sails. The term covers a variety of boats, larger than small vessels such as sailboards and smaller than sailing ships, but distinctions in the size are not strictly defined and what constitutes a sailing ship, sailboat, or a...
, used to extend a sail
Sail
A sail is any type of surface intended to move a vessel, vehicle or rotor by being placed in a wind—in essence a propulsion wing. Sails are used in sailing.-History of sails:...
and control the shape of the curve of the foot of the sail. It runs from the clew (the back corner of the sail) to the end of the boom
Boom (sailing)
In sailing, a boom is a spar , along the foot of a fore and aft rigged sail, that greatly improves control of the angle and shape of the sail. The primary action of the boom is to keep the foot of the sail flatter when the sail angle is away from the centerline of the boat. The boom also serves...
. The line is pulled taut to the appropriate tension
Tension (mechanics)
In physics, tension is the magnitude of the pulling force exerted by a string, cable, chain, or similar object on another object. It is the opposite of compression. As tension is the magnitude of a force, it is measured in newtons and is always measured parallel to the string on which it applies...
to provide the desired shape to the foot and then secured to a cleat
Cleat (nautical)
In nautical contexts, a cleat is a device for securing a rope. The traditional design is attached to a flat surface or a spar and features two “horns” extending parallel to the deck or the axis of the spar, resembling an anvil....
on the boom.
The details vary, but the two most common methods are:
- A knot, usually a bowlineBowlineThe bowline is an ancient and simple knot used to form a fixed loop at the end of a rope. It has the virtues of being both easy to tie and untie. The bowline is sometimes referred as King of the knots because of its importance...
, is tied to a grommetGrommetthumb|right|250px|Some rubber grommets.A grommet is a ring inserted into a hole through thin material, such as fabric. Grommets are generally flared or collared on each side to keep them in place, and are often made of metal, plastic, or rubber. They may be used to prevent tearing or abrasion of...
provided for the purpose in the clew of the sail, then fed directly to the cleat. - The line is attached to the boom, lead through the same grommet, and thence to a cleat; this system provides a factor of two mechanical advantageMechanical advantageMechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Ideally, the device preserves the input power and simply trades off forces against movement to obtain a desired amplification in the output force...
over the previous one.
The outhaul, besides simply holding the sail out, is an effective sail shape control. Tightening or slackening the outhaul can flatten or fill out the sail, shift the draft
Draft (sailing)
In nautical parlance, the draft or draught of a sail is a degree of curvature in a horizontal cross-section. Any sail experiences a force from the prevailing wind just because it impedes the air's passage...
forward or aft
Aft
Aft, in naval terminology, is an adjective or adverb meaning, towards the stern of the ship, when the frame of reference is within the ship. Example: "Able Seaman Smith; lay aft!". Or; "What's happening aft?"...
, change leech and foot tension, and increase or decrease camber
Camber
Camber may refer to a variety of curvatures and angles:* Camber angle, the angle made by the wheels of a vehicle* Camber thrust in bike technology* In the steel industry, the concavity of rolls...
.