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Sailing Basics. Where Are We Going?. Our Sailing Area. Our Boat “Sundancer”. Sailing Basics. Sailing is a lot like flying an airplane, the physical forces that keep an aircraft aloft also cause a sailboat to move forward.
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Sailing Basics Sailing is a lot like flying an airplane, the physical forces that keep an aircraft aloft also cause a sailboat to move forward. Strangely enough, most people have never given much thought to how and why a sailboat moves except to guess that the "wind blows into the sail and pushes it along". If that were the case, a sailboat could only go with the wind. Reality is that they go into the wind as well!
Sailing Basics A sail is a vertical airfoil the same as an airplane wing, and the big secret (to non-sailors) is that sailboats have an underwater wing (that most folks don't see) called a keel, centerboard, or daggerboard. Now imagine an airplane turned up on its side with one wing in the water and the other in the air.
Vector Forces Because of the difference in pressure between the two sides of the sail created by the Bernouli effect, the boat is pulled in the direction of A. If we break down A into two parts, we get two “forces” in the directions of B and C. Since the keel (underwater wing) at the bottom of the boat checks the “force” that tries to move the boat in the direction of C, the boat has no choice but to move in the direction of B
Points of Sail It's not 100% efficient as no sailboat can go more than 30 degrees into the eye of the wind (on either side), but that leaves 300 degrees of direction in which to sail. When the wind is directly behind the boat, it does blow into the back of the sail and "push" the boat along, but the boat does not sail as well "downwind" as it does across the wind.
Sailing Nomenclature What's in a name? When it comes to sailing, and learning to sail, a handle on the basic terminology presents a level playing field and is infinitely preferable to "pull that thing over there."
Lines, Sheets, Halyards & Knots Bowline Lines – used to tie up the boat Sheet – used to trim the sails Halyard – used to raise/lower the sails