Each L. and S. rule for rating racing yachts must have a turning-point, or best length, in each class for winning prizes in a given climate. It depends far more upon the average wind-pressure during the racing season than on any assumed connection between L. and [V¯]S. It will vary on different days, and for different seasons, and for different localities. The average wind-force is stronger on the Solent than on the Clyde, and stronger at Rothesay than at Sandy Hook. But type is another matter. Type is governed by the racing rule, and differences of climate have very little effect upon it. The best proportional length also varies in different classes, the water being rougher and the wind harder, comparatively speaking, on small than on large yachts, thus causing the former to develope L. and sacrifice S. to the utmost. Under the tonnage rules it is true that the small yachts carried the larger comparative sail-plan, but this was due to other causes, such as their greater comparative draught and ballast. The _best length_ under L. and S. rules also varies with the rating rule, those rules having sail-curves nearest to the line R. = S. developing the greatest length, and those having sail-curves nearest to the line R. = L. developing the greatest sail. Still another factor governs the _best length_ in any class, viz. lightness of construction; and this depends on four other factors: cost, design, workmanship, and strength of materials. We are therefore met by quite a crowd of considerations when endeavouring to determine _best length_; but in comparing the rating rules we can eliminate many of them by making a few assumptions and reasoning therefrom. _First_, assume that a new boat is built with the lightest possible hull consistent with strength, and of the best possible design for the 40-R. class 1894, and that her L.=62 ft., therefore S=3,871. (See preceding table.) _Second_, assume that a longer boat and a shorter boat equally well built and designed are tried and are beaten, and that 62 ft. is then acknowledged to be _best length_ for 40-ratings in our climate. _Third_, assume that the class is converted in 1895 into one rated at 61.5 American R., 'Queen Mab' being thereby placed at the top of the class by the Seawanhaka rule without alteration. The 62-ft. yacht, however, must clip to 3,721, or 150 off her S. as a 40-rater. But the shorter boat, say a 'Queen Mab' 59 ft. L.W.L., which we assumed to fail when racing under our rule, could now _add_ 30 ft. and sail against the crack 62-footer with an advantage of no less than 180 sq. ft. of canvas.