The table affords evidence that a rule for apportioning time upon the sail spread, as found by the formula ( / x (L x 6), would be more just in its operation so long as depth varies as the cube root of the beam; but some other mode of ballasting might be introduced which would influence the value of depth. This very possibly might be the case, but it is scarcely an argument in favour of retaining a rule which, as can be proved, is actually inaccurate in its operation.
The measurement most generally urged as the best to replace the Thames rule is that of displacement ; but it cannot be contended that displacement of itself would afford any means of calculating the relative capabilities of different yachts. This was clearly shown in the last chapter, and the inference is that, if displacement were made the standard of value for competitive sailing, yachts would be built shallow and broad, in order great sail area might be carried upon a small displacement. It has been suggested that this tendency of the rale could be checked by making the displacement bear a certain minimum proportion to the length, breadth, and depth, or, in other words, that there should be a limit to the coefficient of fineness ; but any limitation in this way, if otherwise unobjectionable, would not realise the desired object, as the proportion of displacement to the length, breadth, and depth would, under any circumstances, be pretty much the same in either a deep or shallow yacht.
The broad and shallow yacht would carry the largest amount of canvas, and so would have the greatest speed. As speed is the desi deratum in racing yachts, it is right that a designer should be left entirely uncontrolled in developing that quality for a certain value— say the displacement. This appears to be reasonable enough, and would be entirely unobjectionable if no other qualities were sought in a yacht than those of mere speed. But, as yacht racing is not so much the aim of yachtsmen as cruising, they very properly look with great suspicion upon any innovation that would be likely to introduce a yacht deficient in the sterling qualities that the present type are known to have.
To forcibly illustrate the nature of the deficiencies that might be expected in yachts if displacement became the standard of value for yacht racing, we can take the case of the Seabelle and Columbia. The internal (available) capacity of the two yachts is about equal, but the expense of working the Columbia would be at least 50 per cent. greater than the expense of working the Seabelle. A yacht like the Columbia would be an indifferent sea boat, and her great spar and sail area, that would be of such importance for smooth-water sailing, would be only a dangerous incumbrance in a sea ;* further, there is the positive danger that such a yacht might capsize if unskilfully handled. These deficiencies are quite sufficient to horrify any English yachtsman ; and supposing that displacement became the basis for time allowance in competitive sailing, the only advantage of a Columbia would be that she would win prizes if matched against yachts of the Seabelle type. Thus, whilst we are fully alive to the objections to the Y.R.A. rule, we are entirely opposed to the proposal, most generally advocated, to change it for that of displacement : for the reason that, whilst the Y.R.A. rule places some check upon the full development of speed, it induces good sea-going qualities ; whereas a measurement by displacement, whilst admitting unrestricted development of speed, would induce very bad sea-going qualities.
Whilst rejecting displacement if used by itself as a standard of competitive sailing, we are of opinion that it could be satisfactorily used in connection with the manner it enters into the calculation of statical stability. A rule based upon the statical stability of yachts would be unerring in its application, and if any number of competitors had equal stability success would be dependent upon form, apart from influences which may be termed accidental ; but as exact calculations of stability involve such immense labour, we see no prospect of such a scientific test ever being applied to match sailing.