Yachting, Vol. 1 - Sir Edward Sullivan; Earl Thomas Brassey Brassey; R. T. Pritchett; C. E. Seth-Smith; Watson. G. L.

Some trouble was taken in 1884 to produce a special time scale for this formula. It was quite unnecessary, because the time scale for tonnage (see [XVIII.]) then in use could have been employed, (XV.) A being modified to

R = L³ ÷ constant (XV.) B

and by adjusting the constant this form of the length rule can be adapted to the time scale of any cubic rule. Thus, the divisor 5,000 adapts it to the Y.R.A. time scale for rating.

The type resulting from the length rule was, of course, a very fast and powerful boat for its L., carrying an enormous sail-spread—somewhat costly to build and race.

Our grandfathers raced their yachts under the old tonnage rule,

Tonnage R = L × B × H ÷ 96 (XVI.)

H. being depth of hull to deck beam, and L. being measured in various ways at different times. After 1854 it was taken on deck from stem-head to sternpost, and certain deductions made for rake. Eventually the Thames Rule,

(L - B) × B × ½B ÷ 94 or B²(L - B) ÷ 188 (XVII.)

The Rating Rules and Proposals

Date	No. in text	Name of rule or proposal	Rule or proposal			Examples
Date	No. in text	Cubic rules	Variable ÷ constant			Decima	Doreen
1886?	I.	Y.R.A. rule (Dixon Kemp)	LS	÷	6,000	9.98	9.96
1892	II.	Ditto modified (Watson)	(2L+2B÷D)S	÷	17,000	10.06	9.89
1892	VIII.	New York modified (Dixon Kemp)	L² √S	÷	6,000	8.69	9.56
1892	X.	Y.R.A. modified (Dixon Kemp)	(L²S)/^[3]√W	÷	10,000	8.80	?
1892	VII.	Seawanhaka modified Y.R.A. Committee's rule	(L+ √S)³	÷	48,000	9.39	9.75
1892	XIII.	U.Y.F. rule (Godinet)	G(4L-G) √S	÷	520	8.57	9.02
1892?	XIX.	Old French rule	G²(2L-B)	÷	176	12.58	13.53
1876?	XVI.	Old English tonnage rule	L B H	÷	96	?	10.60
1876-80	XVII.	Thames tonnage rule	B²(L-B)	÷	188	15.9	?
1880-86	XVIII.	Y.R.A. tonnage rule	B(L+B)²	÷	1,730	13.8	17.9
	XIV. C	Richardson's rule, cubic form	S √S	÷	6,000	9.97	15.7
	XV. B	Length rule, cubic form	L³	÷	5,000	9.08	11.01