The Lipton Yachts

Sun (Auckland), Volume IV, Issue 1028, 19 July 1930, Page 6

The Lipton Yachts

INTERESTING COMPARISONS

Advantages of Bermudian

Yachtsmen throughout the world are eagerly watching the results of the trial races of Shamrock V., Sir Thomas Lipton’s new yacht, with which he hopes to capture the America’s Cup from the United States. The race will take place in September, but already Shamrock V. is undergoing her trials on English waters before sailing across the Atlantic. A superimposed plan of three famous yachts—Shamrock V., Shamrock IV. and Candida —has been made by the designer of all three, Mr. Charles Nicholson. This plan, which is reproduced here, is of great interest to yachtsmen in all parts of the British Empire, as the race is a classic and every Englishman’s hopes are centred on Sir Thomas Lipton’s new vessel. The distinctive appearance of Shamrock V.’s new sails was the subject of comment when she made her first trial run. Nothing quite like them had been seen previously on racing craft in English waters. The three drawings are on exactly the same scale, so that comparisons are easy. Mr. Nicholson designed the three vessels to meet entirely different conditions. Shamrock IV. was built to a load water-line length of 75ft, on

which length her extreme draught of water was restricted, excepting under severe penalty, to 13ft 9in, but under no restriction whatever as regards height or area of sail plan, lightness of construction, freeboard or amount of rating under the Universal Rule. In Mr. Nicholson’s superimposed plan Shamrock V. is shown by the tinted portion; the dark, broken line is Shamrock IV., and the spaced, dotted line is Candida. An interesting fact regarding the sail plans of Shamrock IV. and Shamrock V. is that, although the older vessel has 50 per cent, greater area, the present challenger has actually the higher mast of the two. Shamrock IV.’s big jack-yarder naturally gives her a lot more upper canvas and, although she is 6£t shorter on the water-line than Shamrock V., her main boom is no less than 24£t, which is 6in longer than that of Sir Thomas Lipton’s new boat. Another interesting point which will he noticed in the sail plans of the three yachts is the difference in the relative proportions of their respective fore triangles. It will be seen that the luff of Shamrock V.’s jibtopsall makes a very acute angle with the fore side of the mast—this angle being only about 18 degrees, as against 20 degrees in the case of Shamrock IV.’s and 25 degrees In that of Candida.

In every particular excepting one—that of the proportion of draught to length on water-line—Shamrock V. and Candida differ from Shamrock IV. These two, In turn, while being simi-

lar in proportion of displacement to length and in construction (both being built to Lloyd’s), differ also in certain features. One of these, which can be seen in the drawings, is that of area and distribution of the sail plan. The following particulars show the extent to which the three yachts differ in their essential features: Shamrock V. —Line water-line, 81.00 feet: sail area, 7,647 square feet; beam, 19.62 feet; draught, 14.70 feet; displacement, 133.43 tons. Shamrock IV. —Line water-line, 75.00 feet: sail area, 11,506 square feet; beam, 22.40 feet; draught, 13.75 feet; displacement. 118.00 tons. Candida. —Line water-line, 79.54 feet; sail area, 8,405 square feet; beam, 20.50 feet; draught, 14.45 feet; displacement, 128.40 tons. The difference between the rigs of the two Bermudians, Candida and Shamrock V., may appear to be somewhat strange, but it is obvious that Shamrock IV. not only required greater sail area, but also a different rig from the other two. The marked difference both in contour and relative areas of the two vessels is explained as follow; The difference in the relative areas is due to an essential difference in the rating rules to which the yachts have to be built. The influence of the inter-

national and universal rules as regards the relative values of “length” and “sail area” is so different that the only wonder is that the divergence from this particular is not even greater. The international rule for the big class, shortly to be withdrawn by the 1.Y.R.U., is what is termed a length and sail area rule, while the universal, or New York Yacht Club’s, rule, Is to all intents and purposes a sail area rule. If unchecked, the tendency of the international rule is to favour too great a rail area for comfortable racing, while the tendency of the New York Yacht Club’s rule is to encourage an undue length and displacement in relation to the amount of sail area that practically constitutes any given rating. The difference in contour is an entirely different cause, and one which is in no way connected with the action of the two rating formulae. The American attitude to the Bermudian rig for big vessels has been: If it is a desirable type of sail plan, by all means let us have it in its most effective form. The British attitude has been; We suppose the Bermudian rig has to come, but by all means let us make certain that it comes only In a safe form. How the American version of the Bermudian rig on big vessels will stand up to Its work has yet to be proved, says a British writer, but from the points of view of appearance and effectiveness there can be no doubt that it scores all along the line.