AMERICA CUP.

Oamaru Mail, Volume XXXIX, Issue 12260, 10 June 1914, Page 2

AMERICA CUP.

launching of SHAMROCK IV. j

HER CONSTRUCTION

,By \V. F. Corbett.)

The cabled information that Sir rri I iuton's vacht bliainrock IV., kto<=t British challenger for the \merica Cup. was launched at Gosport, England is more than interesting—it r %i evinp. A fear existed during the j act couple of months that the boat •l.t Tint, be readv. Some American papers openly declaml that such would to information published , from time to time, Shamrock I\ - is a . centre-beard craft,-the lull is ot com-no-ite construction —steel irallies and fvood-planking-and she has hollow masts of wood. Hie yacht was to have been launched some time last montlr. Charles E. Nicholson, the builder, RCu at rest all rumors about the challenger for the America Cup by a statement he 16 He explained that the delay in tlic construction of the hull was due to some difficulty in obtaining delivery ot tho aluminium alloy, which entered largely into its construction. There were some . points about the design on which Jlr Nicholson was reticent. He naturally wished to keep secret the dimensions ot the vessel, its displacement, and its sail ■ .area These, if previously announcerl. might have had some effect on the plans of the three "defenders being built in New York, as it wa,s not too late to make radical changes, Mr Nicholson did not sav for what purpose the aluminium alloy waa ..needed, but it wa» probablvused for deck plating, and to bo covered with canvas.or cork, inis would reduce the weight abovo tne waterline considerably. . One of the most; interesting ■ eaturc-s of tho new boat is lior. ccntre-boain. inasmuch as she will be the first liritun challenger for the America Cup so fitted. The centre-board has never found' much favor with_ yachtsmen m America, at least for big vessels, cud of tho chief objections against it being the interference with internal accommodation. American designers adhered to it, so far as tlie clip defenders wore concerned, until the \f'kyrie 11.Vigilant contest in 1893. All the HerTeshoff defenders since that date nave been fixed keel boats. The return of the centre-board is due to the fact that under the universal rule of measurement- to which the coii- | testing boats arc being _ built for the forthcoming races, excessive draught is penalised, while tinder the deed of gift which governs cup contests a .centreboard is not measured. Hence it lias been again adopted by Herreshoif and Nicholson. . It was generally, known for some time past that Shamrock IV. -was to be of composite construction. Her planking is of mahogany. All previous Shamrocks were of metal construction throughout. Mr Nicholson stated his • reason for reverting to the wood skin for his vessel. In the first place, had she been built of metal throughout there would .have been the difficulty or riveting. The rivet heads have to be counter sunk flush on the surface to give a perfectly smooth surface, anq with plates so thin as they necessarily must be. there would be considerable difficultv in making the rivets hold. The loosening of rivets, was a. constant source of trouble in connection witb tho construction of Shamrock 11. Then there was the buckling to taka. into consideration. AVith the hammering up of the rivets-there was almost bound to bo some expansion of the thin plates, which induces, the buckling between the frames. Taking all these considerations into account, Mr Nicholson believed that the lines ot his vessel would be more, truly .preserved ■ in a. wood skin, in which there is also more resistance than in metal. _ The boat was being built very similarly to the methods adopted m the putting together:, of .small racers, moulds being set lip to insure- that the frames conformed .exactly with the sections as designed., The making of the mast must m itself have been a-very-interesting operation. Two masts.. were to have been readv by the time the boat was launched, for, as. ..Mr , observed "we almost ..expect the loss of a' mast 'as one of flia.. ..incidents in the tuning up of an America Cup competitor." Tlie masts. t'6 lieto _ been the biggest spars or that description ever built. •