Sailing into the wind is a
sailing
Sailing employs the wind—acting on sails, wingsails or kites—to propel a craft on the surface of the ''water'' (sailing ship, sailboat, raft, Windsurfing, windsurfer, or Kitesurfing, kitesurfer), on ''ice'' (iceboat) or on ''land'' (Land sa ...
expression that refers to a
sail boat's ability to move forward despite heading toward, but not directly into, the wind. A sailboat cannot sail directly into the wind; the closest it can point is called ''
close hauled
A point of sail is a sailing craft's direction of travel under sail in relation to the true wind direction over the surface.
The principal points of sail roughly correspond to 45° segments of a circle, starting with 0° directly into the wind ...
'', typically at an angle of about 45 degrees to the wind.
This maneuver is possible due to the interaction between the
sail
A sail is a tensile structure, which is made from fabric or other membrane materials, that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail-powered land vehicles. Sails may b ...
s and the
keel
The keel is the bottom-most longitudinal structural element of a watercraft, important for stability. On some sailboats, it may have a fluid dynamics, hydrodynamic and counterbalancing purpose as well. The keel laying, laying of the keel is often ...
. The sail generates
lift
Lift or LIFT may refer to:
Physical devices
* Elevator, or lift, a device used for raising and lowering people or goods
** Paternoster lift, a type of lift using a continuous chain of cars which do not stop
** Patient lift, or Hoyer lift, mobile ...
(similar to an airplane
wing
A wing is a type of fin that produces both Lift (force), lift and drag while moving through air. Wings are defined by two shape characteristics, an airfoil section and a planform (aeronautics), planform. Wing efficiency is expressed as lift-to-d ...
), and the keel resists lateral movement through the water, converting the side force from the wind into forward motion. Although the sail force acts partly sideways, the keel’s counteracting force keeps the boat on course and propels it forward.
[Sailing: From Work to Fun]
SEED, Schlumberger Excellence in Educational Development, Inc. Retrieved on: 2010-06-11
The more precisely the sail is trimmed (angled closer to the boat’s centerline), the more the resulting force is directed forward rather than sideways.
To reach a destination directly upwind, a sailboat must
tack
Thermoproteati is a kingdom of archaea. Its synonym, "TACK", is an acronym for Thaumarchaeota (now Nitrososphaerota), Aigarchaeota, Crenarchaeota (now Thermoproteota), and Korarchaeota (now Thermoproteota), the first groups discovered. They ...
— alternate between
port and starboard
Port and starboard are Glossary of nautical terms (M-Z), nautical terms for watercraft and spacecraft, referring respectively to the left and right sides of the vessel, when aboard and facing the Bow (watercraft), bow (front).
Vessels with bil ...
close-hauled courses. This
zigzag
A zigzag is a pattern made up of small corners at variable angles, though constant within the zigzag, tracing a path between two parallel lines; it can be described as both jagged and fairly regular.
In geometry, this pattern is described as a ...
pattern allows gradual progress toward the wind.
Points of sail
Sailing terminology defines various orientations to the wind, known as
points of sail
A point of sail is a sailing craft's Course (navigation), direction of travel under sail in relation to the true wind direction over the surface.
The principal points of sail roughly correspond to 45° segments of a circle, starting with 0° dir ...
. When a boat is
head to wind — pointing directly into the wind — it loses
momentum
In Newtonian mechanics, momentum (: momenta or momentums; more specifically linear momentum or translational momentum) is the product of the mass and velocity of an object. It is a vector quantity, possessing a magnitude and a direction. ...
and
steerage
Steerage is a term for the lowest category of passenger accommodation in a ship. In the nineteenth and early twentieth century, considerable numbers of persons travelled from their homeland to seek a new life elsewhere, in many cases North Amer ...
, a condition known as being in irons. Therefore, when a boat is said to be "sailing into the wind," it is in fact sailing
close-hauled.
Attempting to sail too close to the wind is called pinching, which reduces speed and efficiency.
[Dryden, R]
Glossary
It may also cause the sails to luff (flutter) and lose drive.
References
{{reflist
External links
Counterintuitive Performance of Land and Sea Yachts
Nautical terminology