In windsurfing, how does a 4m sail catch the wind better than a bigger sail? and why are they used for racing?

Question

In windsurfing, how does a 4m sail catch the wind better than a bigger sail? and why are they used for racing?

Answer 1

They are probably used for racing to keep it equal so that a person's skill becomes more of a factor.   There is no real advantage to being overpowered.

Answer 2

To begin with a 4m sail does not catch the wind better than a bigger sail as when the wind is say twenty knots you might use a 6m sail and an 8.5 when it is 12 knots so the size of sail is relative to the wind speed. Also 4m sails are not generally used for racing but in this size they are usually wave sails.