Left: Team NZ’s light-medium air board shows the upward rotation employed to keep the big foil clear of the water when raised. No handlebars for Blair Tuke (below); instead Pete Burling’s 49er gold medal partner uses a ‘Game Boy’ to keep the dot in the best place on the screen for optimal flight while his forearms are secure on these carefully shaped rests. Opposite: ‘When We Were Kings’ – the J Class racing during the Cup regatta was magisterial; this 1930s recreation looks rather modern with everything beside the teak deck seemingly built out of carbon…
systems from talking to the control systems, and demand that all movements of controls are in response to an unmolested human input. But there is nothing in the rules that says an autopilot computer code that senses the boat state can’t be used to give the crewmember cues as to where the ‘best’ position for a particular control is. I am pretty certain that Blair Tuke was
looking at a display that showed him where the board needed to be every moment of every race. That’s the reason he spent all his time staring down, he was following the bouncing ball. The arm restraints (left) ensured he retained precise fingertip control. It was the use of this auto pilot cueing that let them tack fast and recover from some ridiculous high-flying moments that others would have crashed down from. If you want to get stuck into this read AC Class Rule Interpretation 70. So there you have it: a truly synergistic
input to zero while he is operating the controls. If, however, you put him on a bike his hands are free and he can pedal. I like to think that the cycling grew from the need to free up an extra pair of hands. Once you have one set of pedals to liber-
ate a third pair of hands, having everyone pedal is a natural progression. You get a 20-30 per cent power increase using legs rather than arms. Widely predicted delays getting on and off the bikes never materi- alised. So now the helmsman can steer the boat, untroubled by keeping the ride height correct, plus he is free to mode the boat and manage the position on the course. The wing trimmer trims the wing and the third man has control of ride height. In straightline sailing the helmsman is
quite capable of adjusting the single dagger board to maintain level flight, but in manoeuvres it is a different story. When turning, both boards need to be adjusted in tandem to make sure the new board enters the water smoothly without taking any load. Once both boards are fully down the turn can be initiated and the lift transferred from the old board to the new board. Only once established on the new tack can the old board be lifted clear of the water. Obviously in straightline sailing you use
the leeward board to provide the lift so as to move the centre of lift as far to leeward as possible, maximising righting moment. But during the tacks and gybes when the wind is directly ahead or astern righting moment doesn’t matter, so supporting the boat on both foils is OK. In fact, it is more
than OK – at low speeds dividing the lift between the two foils creates less drag than having one foil do all the work. So now the dedicated foil controller can
fly the boat through the tacks making sure that the transfer of load from board to board is optimal. This extra degree of co- ordinated foil control when the helmsman is normally running across the boat brings a speed and reliability to tacking and gybing. As touching down during man - oeuvres is very costly in light winds this gave ETNZ another leg up. The ETNZ helmsman could literally hurl the boat through tacks safe in the knowledge that the foils would look after him. Once the manoeuvre is complete the third man crosses the boat at a time of his choosing. The final bit of this three-piece jigsaw is
the human machine interface (HMI). Everything is controlled by hydraulic rams, the foils and wing flaps and sheet position. The flow of hydraulic fluid from the accumulators (think hydraulic batteries) is controlled by valves that are controlled by signals generated from a controller that is attached to a computer. This means that the controls can be anything you want: buttons, twist grips, foot buttons, sliders and so on. Also the adoption of electro- mechanical control means that it was a rel- atively simple step to couple the instrument system and the actuator control to give the boat an automatic ride height mode. I expect that most teams experimented
with this to optimise control strategies. For racing the class rules forbid the instrument
system, finer control and more power so you can use the controls more often. Racing on short courses between boundaries means that it is hard to keep pace with hydraulic oil demand from the board and rudder rake rams and the wing control. Every team gets down on accumulator pressure if they do a couple of unplanned manoeuvres, and this starts to degrade sailing performance and soon strategy is compromised by not having the oil to tack or gybe. If you have 1,000 watts of Olympic
quadriceps charging the system it’s not so much of a problem. Having this extra power-generation capacity also means that the wing trimmer gets a helping hand – no winch and rope for Glenn Ashby, he had a modified Game Boy-style controller that let him trim wing sheet, base camber and twist as if he was playing a video game. Was all this a surprise, probably not, but
the excellence of the execution and the performance margin over the rest of the fleet, particularly in light airs, was absolutely gobsmacking. Oracle didn’t waste the week between
races four and five, they lightened the boat, fitted smaller rudder elevators and I think added a couple of hundred millimetres to their daggerboard tips. All logical steps to improve light-air speed. These are develop- ments that most teams made during the Challenger eliminations when ETNZ’s per- formance became clear, but your room for massive performance jumps is limited. In terms of reducing weight, I’m sur-
prised Oracle were not racing at minimum SEAHORSE 41
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