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

Date	No. in text	Name of rule or proposal	Rule or proposal			Examples
Date	No. in text	Linear rules	Variable ÷ constant			Decima	Doreen
1882?	III.	Seawanhaka rule	L+ √S	÷	2	38.33	38.82
?	IV.	New York rule	2L+ √S	÷	3	37.45	38.57
?	V.	Y.R.A. Rule (Dixon Kemp)	^[3]√LS	÷	1	39.12	39.11
1893	XI.	Y.R.A. modified (Thalassa)	LS/M	÷	72	37.23	38.34
1893	XII.	Seawanhaka ditto (Thalassa)	L + √S - √72M	÷	1	36.71	38.23
1893	IX.	Herreshoff's new rule	L √S/^[3]√T	÷	15	38.69	37.01
1892	VI.	Watson's rule, linear form	2L+2B+D+ √S	÷	3.8	37.60	38.58
?-86	XV. A	Length rule	L	÷	1	35.65	38.05
1886	XIV. B	Richardson's rule, linear form	√S	÷	1	41.00	39.60

The following Dimensions were used in the Examples

——	L	L²	S	√S	B	D	G	M	W tons
Decima	35.67	1272	1679	41.0	11.0	8.5	36	22.2	14.3
Doreen	38.05	1448	1572	39.6	11.2	8.5	36	21.7	?

N.B.—G is only approximately correct. It is measured in the French way was evolved and adopted by the Y.R.A. in 1876. And in 1878 it was decided to measure L. on the water-line. In 1880 the Y.R.A. altered the rule to

English T = B(L + B)² ÷ 1730 (XVIII.)

The type evolved, as might have been anticipated, had a long, narrow, heavily ballasted, deep-bodied, wall-sided hull, possessing little beauty, small initial stability, and no great speed, considering the sail-area employed to drive it. There was little scope for improvement, and the energies of our best designers were directed to producing yachts which carried large sail-plans on narrow hulls, their L.W.L. often approaching and sometimes exceeding six beams. Nevertheless, this '1730 Rule,' as it is often called, governed first-class racing in British waters from 1880 to 1886.

Another hull-measurement rule is the one used for some time in France, and often called the 'Girth Rule.' In its simplest form, it was:—

French T = G²(2L - B) ÷ 176 (XIX.)