What limits the speed of a sailing yacht?

[admin]

The theoretical maximum speed of the hull is limited by the waterline length.  As the boat moves through the water a small wave appears either side of the bow.  As the speed increases a second pair appear further aft.  As the speed rises these waves get larger and further apart until the boat "hangs" between the bow wave and the second wave near the back of the yacht.  This velocity is the maximum that the hull can reach without planning (riding above the water).
Hull Speed = square root waterline length in feet x 1.33

Very narrow hulls of light displacement and shallow body draught like Stan increase the value of the multiplying constant.