Similarly, the Y.R.A. rule--varying as [3V¯]L.S. (see V.), or as [3V¯]L. × [V¯]S. × [V¯]S.--may be considered as equivalent to the plus formula L. + 2 [V¯]S. ÷ constant, and the English and American rules may therefore be regarded to vary as follows: In linear measure New York as 2 L + [V¯]S Seawanhaka as L + [V¯]S Y.R.A. as L + 2[V¯]S Mr. Herreshoff has recently proposed a rule of rating based on L. [V¯] S., which is an area, but the cube root of tonnage is placed in the divisor; and this being linear, it converts the rating into linear measure, an area divided by a line being a line. The result being linear, it is translatable into American rating and time allowance. Mr. Herreshoff's proposed rule is:-- American R = ( L [V¯]S / [3V¯]T ) ÷ constant, say 15 (IX.) A critique on this rule by the editor of the 'Field,' December 17, 1892, suggests that the cube root of 100 T. should be taken, as there are 100 cubic feet in a registered ton. This is unnecessary. So long as S. is superficial, and T. cubic, the [V¯]S. and the [3V¯]T. will be linear; and a constant can be selected which will convert the quotient resulting from the rule into corrected feet or inches, or metres, as required for the linear rating adopted. Mr. Herreshoff's rule when tested is not encouraging; 'Doreen's' length so corrected being 2-1/2 per cent. smaller than 'Decima's.' The rule evidently does not encourage that compactness of hull-dimension which Mr. Watson considers desirable. It also appears to put a premium on abnormal freeboard, so as to increase T. by means of a large body over the water-level. This was pointed out by the editor of the 'Field,' December 24, 1892, and an improved rule suggested in which displacement was used as a divisor in place of tonnage. W. the total weight of yacht in English tons dead weight is of course her displacement, and the rule proposed may be written:-- English R = ( L{2}S / [3V¯]W ) ÷ 10,000 (X.) So far as L. and S. are concerned this rule would produce a similar sail-curve to the Y.R.A. rule (see diagram); but the divisor would encourage a large powerful hull, and the rule would therefore produce a shorter type with more sail than now exists in English racers. The practical difficulty of discovering W., either by measurement or by some system of weighing the yacht complete, has to be considered in connection with this rule.