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MARCH TWO U.S.A. 1962 SHILLINGS & CANADA FORTY CENTS Inside: Turbo Jets for Model Ships Model Boats! STETAIE IANKIE’R} [NS the notes which accompanied the publication of Top Hat, I mentioned the three basic types of A Class yacht which could be successful under most conditions. Top Hat is what one may term a compromise type and I have since prepared the design of Vital Spark and there is no compromise about this. Here we have minimum L.W.L. possible for maximum sail area with minimum displacement. Vital The L.W.L. beam is kept down to the minimum Spark THIS A LATEST CLASS 1,545 sq. JOHN DESIGN ins ON WATERLINE, LEWIS CARRIES A 54 51.7 Ibs. DISPLACEMENT in. practicable without having to have a deep canoe body. The beam on deck is very narrow due to heavy tumblehome reducing the difference between “In and Out” wedges. The thickness of the keel is the minimum practicable for reasonable ballast distribution. The freeboard is very close to the minimum allowed by the rules. It is important that the design is built accurately otherwise freeboard, draught and displacement penalties will be incured. Any reduction in sail area below the designed figure could spoil the usefulness of the yacht under most conditions, but particularly in light weather. It is equally important that all constructional weights be kept down to a minimum so that the maximum quantity of lead is put into the keel. Another point often forgotten during construction is the avoidance of hollows on the hull surface at bow and stern when planking up a hull on ribs as opposed to “bread and butter” methods. The planking of a hull, generally speaking, follows the line of the diagonals and in many designs this curve is pronounced about the midships and almost straight VITAL SPARK John Lewls COPYRIGHT MODEL MAKER 38 CLARENDON wast OF POSITION PLANS BO SERVICE WATFORD WERTS INTERNATIONAL A CLASS YACHT Wie Fi ter he mat fae = ies “ | e — ae | Se |e Leao eee eee OBL—- — + ses DRAFT ~ ~ – e122″ AVERAGE Z- mt LEAD OSPLACEMENT- =\. * 390 + 51 TO eee oe ie r¢ a ——— 4 ras mee d cA —- Sa —-, ie!Cia
