Sailing
Sailing is the skillful art of controlling the
motion of a sailing ship or smaller boat, across a body of water. Sailing
vessels are propelled by the force of the wind on sails. Today, for most
people, sailing is recreation, an activity pursued for the joy of being on the
water and pursuing the mastery of the skills needed to maneuver a sailboat in
varying sea and wind conditions. Recreational sailing can be further divided
into Racing, Cruising and "Daysailing."
www.Luxury-Yachts-Sailing.uv.ro
A boat
moves as wind pushes on its sails. This is obvious when the boat is sailing downwind.
The keel of a boat keeps it from strafing to the sides. This allows a boat to
sail downwind but at an angle. The wind that blows on a sail is deflected off
the sail, and that wind pushes against the sail too. The result is that the
sail is not just pushed straight downwind, no matter which way it faces; but
rather, it is pushed in the direction that it bows. This lets a boat pointed upwind,
though at an angle and not straight upwind, to move forward as long as the sail
is able to bow forward. If the sail is pointed just as the boat, then the boat
will only be pushed sideways, yet if the sail is pointed into the wind, then it
will not catch the wind at all. So, the sail must be pointed somewhere between.
- A boat moves forward with a resultant
force proportional to the dot product of the forward vector of the boat
and the force vector of the sail on the boat. The force of the sail on the
boat is parallel to the average normal vector of the sail and is proportional
to the dot product of the relative wind vector and the average normal
vector of the sail. This proportionality is most obvious because depending
on the angle of incidence of the wind on the sail, the effective area of
the sail varies. So, a positive value for a resultant force on the boat
requires that the angle of the sail be bound between the forward direction
of the boat and the upwind source.
When
sailing downwind, a boat catches up to the wind, so the wind cannot push as
hard on the sails. When sailing at an angle to the wind, however, although the
boat may move fast, it is not catching up to the wind, so the wind continues to
push the boat faster. Of course, eventually the boat cannot move faster because
of the water, but not before speeding along much faster than if it had been
sailing directly downwind.
- The force on a sail is actually
proportional to the relative velocity of the wind to the sail. Many
factors complicate these generalities, however, such as the drag of the
wind on the sails, the drag of moving through the water, the loss of wind
force due to the boat heeling to a side so that the sails are pushed down
and not just across the water. www.Luxury-Yachts-Sailing.uv.ro
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