what is the physics behind sailing?

Question

i sail and i am curious what the physics that powers sail boats is. i am in a physics course so i have a relatively good understnading of basic physics.

Answer 1

Bernoulli principle plays the largest part in sailing on any point of sail from a beam reach to close hauled. Air flowing over the sail (vertical air foil) creates low pressure on one side and high pressure on the opposite side of the sail. The sail is drawn into the low pressure area. If a boat didn't have a keel or other lateral resistance, the boat would "lift" right down wind. By sticking the keel or centerboard into the mix, the boat is provided with a lateral resistance and instead of slipping sideways, a vector is produced for forward motion.

A jib acts to create a slot between the jib and the mainsail, further increasing the speed of the wind (lowering the pressure) for even more forward driving force.

Answer 2

Sailing with the wind is obvious - the force of the wind on the sails blows you forward.

Sailing against the wind is more interesting. This is where the keel of the boat comes in. The keel allows the water to create a resistive force on the boat. Coupling this with the force of the wind on the sail as the boat moves forward but angled to the wind direction gives a net force in the right direction - draw a force diagram.

This is called tacking, as you will know - zig zagging about a line in the direction of the wind.

Answer 3

I don't have experience in Physics, but Wind powers the sail to force the boat to move in whatever direction the sail blocks the wind, blaahhh!@

Answer 4

Arcemedes` principle. The boat floats because the water displaced by the boat under water is heavier than the boat. If the rudder turns right the boat turns right. If rudders on both sides are moved backwards the boat moves forward.