Left: winning the America’s Cup on the drawing board – Davidson generally left the ‘computer stuff’ to others. The critical length measurement on an ACC yacht is taken 200mm above the waterline (where the red and black lines cross) exploited by Davidson with his ‘scow’ profile seen (left) in black on 2000 Cup winner NZL-60 and overlaid onto 1995 Cup winner NZL-32, shown here in red – allowing this ‘free’ extension of the actual waterline. The new bow treatment evolved as a hybrid of the forefoots of the IOR era (centre) and the vertical stems on several final-generation 12 Metres. Andy Claughton (of this parish) was technical co-ordinator at Team New Zealand for the 2000 defence and it his instruction for locating the measurement points (screw heads) that is shown below
pronounced waterline chin at the forward girth station, but instead of rising steeply into an IOR bow it took a shallower incline, more like a Metre bow. It was essentially a hybrid of the two styles. Russell Coutts recalled being surprised
already done. Look at Pendragon IV and just draw a box around it!!’ Another project that demonstrated
Davidson’s ability to think outside the square was his design for the short-lived Ultimate 30 pro sailing circuit. Davidson had plenty of experience of skiff sailing in 18-footers but felt most of the Ultimate 30 skiff designs had got it wrong. He went in an entirely different direc-
tion with a scow-type hull which proved faster than the skiffs upwind and able to match them downwind. When a fuss was made of his Ultimate 30,
Davidson laughed off suggestions that it was a ‘breakthrough’. He told Bakewell-White that the design was inspired by the scow- type ‘skimmers’ that New Zealander Arch Logan designed in the early 1900s (many of which were exported to South Africa). Evi- dence, chuckled Davidson, that ‘in yacht design there is nothing new under the sun’. Arguably, however, Davidson’s proud-
est legacy lay with the America’s Cup. When New Zealand made its Cup debut in 1987 with a bold leap into the world’s first fibre-glass 12 Metres the design team com- prised Davidson, Bruce Farr and Ron Hol- land. ‘Laurie had a fascination for the America’s Cup,’ recalled Bakewell-White. ‘He was a student of its history and,
purely as an intellectual exercise, he had been drawing 12 Metre yachts for years. When the New Zealand Challenge got off the ground he was probably the only one of the three designers who had studied the rule in depth and drawn detailed designs.’ New Zealand’s big breakthrough came
in 1995 when Davidson and Doug Peter- son were the principal designers in a talented group led by 1983 America’s
46 SEAHORSE
Cup-winning engineer and sail designer Tom Schnackenberg. Working to the International America’s Cup Class (IACC) rule which replaced 12 Metres in 1992, the Team New Zealand consensus was to go long and narrow. Of its two new yachts NZL-32 was slightly narrower and longer than NZL-38. Both were great performers: NZL-38
won the Louis Vuitton Cup with only one loss in the 24-race series; then NZL-32 stepped up to beat Dennis Conner’s Stars & Stripes 5-0 to bring the elusive trophy to New Zealand shores for the first time. For the 2000 Defence, with Sir Peter
Blake staying as syndicate CEO, Schnack- enberg was again Team New Zealand’s design co-ordinator in a large group, but now with Davidson and Clay Oliver billed as the principal designers. Quite early in the design process the designers chopped the bow off NZL-38 about 600mm behind the forward girth station and created a pram bow, as on an Optimist. ‘Then we went out on the water and it seemed to go just the same as before,’ recalled Schnack- enberg. ‘We thought, “Here we go!” ‘This boat, under the rules, was now 2ft
shorter. So we could take the entire boat and stretch it 2ft and it would be back to the same rating as before.’ Sniffing worth- while prey, the design hounds were off and running. There were promising results with an almost plumb IOR-type bow, while other investigations pursued a more classic Metre-boat bow shape. ‘Clay Oliver did some work on it and
Andy Claughton was involved too, but Laurie quietly went off on his own and came back with a couple of drawings.’ Davidson’s concept featured a quite
by how full the bow sections were, while Clay Oliver admired Davidson’s much vaunted design eye, which had spied the ‘Goldilocks zone’ between the IOR and Metre boat shapes. ‘It really didn’t look like much until we took it to the towing tank,’ said Schnackenberg. ‘Suddenly at the same fixed speed the drag was a lot less. I was actually a little surprised and excited at how well it worked. ‘By stretching the bow and stern waves
further apart that little chin tricked the water that the hull was longer than it was. When we tested it further we found it was effective in light air and heavier air and also in waves. It had no weaknesses. It is a tribute to Laurie that he came up with it.’ What became known as the Davidson
Bow featured on both NZL-57 and NZL- 60. But as the Match drew near there was a feeling in the defence group that they might have pushed length slightly too hard, so they pared NZL-60 back in exchange for more sail area. ‘We just lifted the bow slope slightly, shortening the rule length by about 2-3in,’ said Schnacken- berg. ‘It demonstrated that the bow was really quite adaptable. You could tune it to the expected conditions. If we were expect- ing heavier air we could probably have gone the other way as well.’ In the hands of a formidable sailing
team NZL-60’s subsequent 5-0 victory delivered the first successful defence of the America’s Cup outside the USA and was testimony to a highly refined all-round design package. There was considerable praise also for the
millennium rig, for example, and the atten- tion generally paid to aerodynamics. But the Davidson Bow will for ever enjoy star billing in the NZL-60 story. ‘Come the Match I would say the bow was the key difference between the boats,’ Schnackenberg declared. Forty more ACC America’s Cup yachts
would be built before the class was retired in 2007; virtually every one of them would feature that same instantly recognisable Laurie Davidson snub nose.
q
ANDY CLAUGHTON
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116
