Course of Cup Design
Total Page：16
File Type：pdf, Size：1020Kb
Course of Cup design Roger Marshall assesses how the rating rules have shaped the Cup yachts over 100 years r'ntil 1983, the America's Cup was changed, in today's Intemational Offshore Rule. Columbia. All the time yachts were getting a symbol of American supremacy. longer. Shamrock, designed by William Fife, Although it has always been an was 2ft Sin short of the 90ft they could be on 2 B event which builds up to fever the waterline whilst Columbia was 2in less than III pitch then fades into obscurity, its L was measured on the LWL. This rule led to this maximum length. Shamrock led in many successful technological developments have the first noticeable burst in development. of the light air races but in heavier winds Col e\'entually filtered down to the general sailing The first match under this rule was in 1885 umbia crossed the line first and won the series. fleet to become an everyday part of production between Puritan, of shallow and beamy design, Constitution and Independence, specially built designs. and Genesta, deep and narrow, in line with for the 1901 challenge, lost in the trials to Col In 1870 Cambria competed against 23 other British design practice. The launching of umbia but not before Independence's scow- schooners and was defeated by Magic. James Gloriana in 1891 moved yacht design in the shaped hull and lightweight construction had Ashbury. Cambria's owner, challenged again in direction of the metre boat style. A new shown surprising bursts of speed. Her con 1871 with Livonia. This time the Americans lin Nathaniel Green Herreshoff design, she had a struction was so light that she leaked and the ed up four vessels ready to race him and the fin keel, 4,00011^ of sail, was 46ft on the hull twisted as she sailed. The match was yet match was won by Columbia and then by Sap- waterline but 70ft overall. She won eight races another victory for New York YC but led to plio when Columbia was disabled. Ashbury pro in eight starts and Herreshoff, to defend the another challenge from the sporting Sir Thomas tested, with the result that any subsequent Cup, designed and built no less than six Lipton. Sliamrock II, designed by G.L. Wat challenger only met one deferider, the racing defenders from 1893 to 1920. He drew son, while extremely fast, was defeated due to format we know today. Gloriana's successor, the centreboarder lack of preparation and experience. She was The rating rules have always played a very Vigilant. Vigilant was criticised during trials, one of the first boats to be tank tested. interesting part in influencing design. The for the new ideas she encompassed. She fac Reliance was the biggest boat ever built for schooners of the early races gave way to sloops ed Lord Dunraven's G.L. Watson-designed the America's Cup. At 89ft 8in on the waterline, with the inception of the Cubical Contents rule Valliyrie II in the 1893 match and won three 143ft 8in overall with a sail area of 16,160ft^ in 1880. This rule calculated the volume under straight races. Lord Dunraven challenged again and a mast of about 190ft, defeated Shamrock the sheerline and led to shallow-draught, beamy with another Watson yacht, Valiiyrie III, a boat III, another Fife design, and ushered in a new boats with a huge spread of canvas. Under this close in design to the American defender. Both era. She was a true extreme yacht: thinly rule the Canadian boat Atalanta was easily boats sported long overhangs, long bowsprits plated, with a towering rig and long overhangs defeated by Misciiiefm 1887 When one of the and deep keels. The match ended acrimonious designed to cheat the 90ft LWL limit. Just five boats taking advantage of this rule sank at her ly when Valkyrie fouled Defender. knots of wind would heel her enough for mooring, drowning all on board, the rule was 1899 saw Sir Thomas Lipton's first challenge Reliance's sailing waterline to increase from 90ft changed. Dixon Kemp proposed what eventual in a boat that pushed the limits of the rule. to 130ft due to her 54ft of overhangs. Thus the ly became the Seawanhaka Rule, taking into ac Shamrock was 129ft overall with the unlikely Universal Rule came into being: count length and sail area. Its final form has combination of manganese bronze plating under Rating = L x SA survived to be incorporated, though slightly the water and aluminium topsides. She raced 5 Disp Olin Stephens, doyen of tiie designers. Right, Dame Pattie in 1967 This is the forerunner of today's rule. Lip- ton challenged again in 75ft wateriine boats. Shamrock IV was the first America's Cup boat designed by Charles Nicholson of Camper & Nicholson fame. She was in the mid-Atlantic when Worid War I was declared and eventually lost to yet another Herreshoff yacht, Resolute, when the races were finally held in 1920. It was in 1924 that the American and British discussed rules and scantlings and the Thames measurement rule gave way to a 'scientific rule' developed by R.E. Froude which eventually became thé International Rule we have today. By 1928 the American Universal Rule had been adopted for boats over a 76ft waterline or J Class boats, while the British International Rule was adopted for boats under this length. CONTINUED OVERLEAF 44 The J Class saw major design changes: the Bermuda rig replaced gaff-headed mainsails, alloy masts replaced wooden spars and winches proliferated and moved below deck. The boats had now become stripped-out rac ing machines and, with new sail developments, were much faster than earlier yachts. Parachute spinnakers, double and triple headsails and Quadrilateral (i.e. double-clewed) jibs came into use. Improvement in headsails and hull design made the 1937 Endeavour II one of the big gest J boats yet built. Olin Stephens and Starl ing Burgess worked together and, with a large amount of tank testing, produced Ranger which ran away with the series and advanced the shape and a very stripped interior. Once again series was marred by some rating interpreta cause of scientific tank testing along the road the defender beat the challenger, the Boyd- tions and decisions which annoyed the Austral to acceptability. designed Sovereign from Britain. ians. When Chance re-designed Intrepid he With the advent of Worid War II, it was not The biggest advance in design came with Olin moved the rudder stock aft six inches and fil until 1958 that the Cup was challenged for again Stephens' masterful Intrepid. Her rudder, with led the space with fairing strips. Thus for and this time it was in 12-metres: boats approx a trim tab at the trailing edge to reduce leeway displacement purposes the boat still had a imately 65ft long, weighing 55 to 60,0001b; less and develop more lift, was removed from the waterline length of 45.5ft but an actual waterline than one-sixth of the weight of a J boat and trailing edge of the keel and placed at the end of nearer 46ft. Alan Payne's Gretel II had a real diminutive compared with the likes of Shamrock of the waterline. The rudder was prefaced by wateriine of almost 46ft making her 1,8001b III and Reliajice. a large bustle — called a kicker — which had heavier. The Americans held trials with four boats and the effect of moving the quarter wave further Major changes were set for the 1974 it was the S&S designed Columbia which went aft and rnaking the boat appear longer in the challenge. Built in alloy Courageous and on to defeat David Boyd's Sceptre, a British boat water. Wetted surface was also reduced by Southern Cross had a significant weight advan criticised for her rounded bows and exaggerated almost seven per cent making the boat poten tage over earlier boats in that the hull struc pitching. A feature of this challenge was the tially faster in light winds. In her first series ture of wooden boats weighed about 15,0001b; new Dacron sails and the open cockpit of Scep in 1967 Intrepid beat Warwick Hood's Dame the remainder of the weight was in the lead tre which was copied by later Twelves until Pattie 4:0. Dame Pattie weighed approximate keel. An alloy boat, on the other hand, had a Courageous almost sank. ly 61,5001b while Intrepid weighed about 56, hull structure at that time of about 10,0001b and the remaining weight in ballast. This had the Four years later in 1962 the AustraEans came 5001b. The lighter boat had better acceleration effect of making the alloy boat stiffer. Mariner, to Newport with Alan Payne's Gretel, a faster in most conditions. another defence candidate, took the In- yacht than the defender Weatlmiy designed by The 1970 series saw a Britton Chance re trepidAMant thinking to its logical conclusion. Philip Rhodes. However, lack of experience design of Intrepid beating Gretel II while Olin prevented them winning. Stephens produced Valiant, the logical next The problem with Mariner was that the The next step in the evolution of the step down the path found by Intrepid. Valiant, model in the towing tank allowed the water to 12-metre came with Constellation in 1964. however, had too big a bustle and was too large be fooled into filling the space behind the chop Another S&S creation, she had a bendy boom, altogether. Olin learned from this and produc ped off stem making it seem as if the boat were a mast light enough to bend to suit the sail ed the superb Courageous for 1974.