Intro to Sailing: How it Works

The way sailing works is quite simple and can be understood with a minimal cranial effort. Sailing uses the winds force to propel a water craft. The concept of a slick suface underneath and a form of propulsion above can be used to move any object. One illustration used a person on a skateboard with an umbrella in hand. The wind catches the umbrella and sends the skateboard forward.

When the sails are rigged in a different direction than the wind the sail itself "splits" the wind. This creates a difference in pressure. The windward side has an increase in pressure while the "leeward" side receives lower pressure. The boat then goes forward to "fill" the vacuum. This effect is also seen with a planes wings. The sailoat is the same basic principle except that it is vertical as opposed to the horizontal plane wing. The bernoulli principle shows this concept.

Now for the surface-contact. Sailboats have a "wing" called a keel. Catamarans and small monohulls have a "centerboard" that fulfills the same purpose. The keel does three important jobs. First it balances the boat. Because of the weight of the sails there must be some couter weight on the bottom of the boat so it doesnt fall over. Secondly, the keel keeps the boat from going "just" downwind. Lastly, when water runs on either side of the keel it creates lift and enables a straight course. The keel directs the lift forward instead of down.