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Sailing Theory, Sailing Terms and Weather
Sailing Theory, Sailing Terms and Weather by Linda Cullum
Sailing Theory The sum of all wind pressure on the sail is called wind force.
The center of that force, which is above the water, is called the center of
effort (CE). The center of the force below the surface of the water is calledthe
center of lateral resistance (CLR). This is the point where all the boat's
resistance to sideways pressure is concentrated. A boat performs best when the
two forces are in balance. This is when they are positioned one over the other
in a vertical line through the boat's sail and hull. Your job as a sailor is to
keep these two forces in proper balance so that your boat will sail correctly.
You keep the boat balanced by shifting your weight and adjusting your sail.
Your boat has weather helm when you have to constantly pull the tiller
towards you to keep the boat straight on course. Lee helm is when you do the
opposite; pushing the tiller towards the sail. Most boats are designed to have a
little weather helm. However, too much of it can make sailing difficult in
anything other than light breezes. If your boat has a lot of weather helm, it
means the CE and the CLR are not in alignment.There is more sail pressure aft of
the CLR than forward of it.
To correct the balance, 1. Shift your weight
aft (back towards the stern). 2. Pull up the centerboard. 3. If your boat has a
jib, ease (let out) the mainsail. 4. Try any combination of these.
Weather- The Sea Breeze
As a sailor you should know about local
winds. The cause of these winds is difference in temperature; cold air is
heavier than warm air. The most popular of these local winds is the sea breeze.
Warm air over the land rises...And is replaced by cooler air sinking over the
ocean. At night the opposite happens. The land quickly loses its heat at night
and oftenfalls to a lower temperature than the water. This results in a light
offshore evening wind. On a lake or river, the warm air can rise at the edges to
be replaced by the cool air over the water. This can result in a nice breeze for
sailing.
Forcast for a Typical Sea Breeze Day: Morning Very Light Winds
-No Weather Systems Near -Clear Sky -High Temperatures But Cooler Near the Shore
Afternoon: Wind coming from water starting Midday -Cumulus Clouds over
land -Clear over water- Winds Speeds 8 - 12 knots
Evening: Winds
Decreasing as sun slips over horizon.
Sailing Terms
Amidships-
the middle of the boat.
Backwind- the wind flowing off the sail.
Close Hauled- one of the points of sail; sailing as close to the wind as
possible.
Dead Astern- straight behind
Flaking- Folding the
sail.
Glide Zone- the distance it take a boat to stop after turningb
head to wind.
Heave To- to head the boat into the wind in order to slow
it down or stop it.
About the Author
Linda Cullum is from Cape Cod, MA, with a second home in Vermont. She is the author of Learn to Sail! with Multimedia! an Interactive Sailing training CDROM which teaches all aspects of Sailing including Knots, Piloting, Rules of the Road, Weather with digital video from Sail Magazine, narration, animation and quizzes. Visit her site at http://learntosail.net Happy Sailing_/)__
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Added: Tue Nov 07 2006
