Sail area-displacement ratio

The sail area-displacement ratio (SA/D) is a calculation used to express how much sail a boat carries relative to its weight. S A / D = S a i l A r e a ( ft 2 ) [ D i s p l a c e m e n t ( lb ) / 64 ] 2 3 = S a i l A r e a ( m 2 ) D i s p l a c e m e n t ( m 3 ) 2 3 {\displaystyle {\mathit {SA/D}}={\frac {{\mathit {SailArea}}({\text{ft}}^{2})}{[{\mathit {Displacement}}({\text{lb}})/64]^{\frac {2}{3}}}}={\frac {{\mathit {SailArea}}({\text{m}}^{2})}{{\mathit {Displacement}}({\text{m}}^{3})^{\frac {2}{3}}}}} In the first equation, the denominator in pounds is divided by 64 to convert it to cubic feet (because 1 cubic foot of salt water weights 64 pounds).

Source: Wikipedia — Sail area-displacement ratio (CC BY-SA 4.0)