Sail area/displacement ratio

Like the Displacement/Length
Ratio, this is a useful parameter in comparing one boat with another. The sail
area is nominal, being that which is enclosed by two triangles, one
representing the mainsail, and the other the area between mast, forestay and
foredeck. Divide that by the displacement to the power
of 2/3. Use square feet for sail area and long tons 2,240lb for displacement.