Update
The singlehanded Firefly fleet race at the 1948 Olympic regatta in Torquay. Before leaving Denmark Paul Elvstrøm (right) was told by the head of his federation, ‘if you don’t come last then we will be happy’. After retiring from the first race following a foul the young Dane’s confidence improved and with it his performance – he went on to win the last two races to secure the first of four gold medals. For Elvstrøm nerves would continue to be an issue at big events, something he concealed masterfully from his rivals for many years
A NEW REGIME – Jack Griffin
In November, the same month that the American electorate voted for regime change, the America’s Cup moved to a new regime as well – the AC Class. And, just as the new American president will not take office until January, the new AC Class will not sail much until January, given that the earliest permitted launch date is 27 December. At just over 49ft long, these mostly one-design yachts will be much the same as and very much
different from the AC45s that the teams have raced in the America’s Cup World Series. Much the same because they will be almost the same size and, to the casual newbie fan, they will look the same: foiling catamarans with wing sails. The new fan may not notice that the new class has only a wing and a jib but no Code 0. He may not notice that there is a crew of six instead of five, that the helmsman has a wheel instead of a tiller and that the crew have grinding pedestals in cockpits. Even the most avid America’s Cup fan will not be able to see some of the most important differences – the hydraulic accumulators and the sophisticated control systems for daggerboards, rudder rake and wing management.
When the AC45s were converted for foiling, batteries and electric motors were added to power the hydraulics for daggerboard rake control. The AC Class Rule prohibits motors but allows three 4.8-litre hydraulic accumulators operating at 350 bar. The original idea for adding accumulators was safety – to ensure that the helmsman would always have enough oil pressure to adjust board rake to avoid an accident. Oracle almost flipped their second AC72 while training in May 2013. There was no response to the board rake controls after the wing trimmer had just bled off pressure changing the camber and twist profile of the wing. But nothing prevents using the accumulators to power normal manoeuvres. In fact, two of the three accumulators may be used
8 SEAHORSE
just to raise and lower the daggerboards. The remaining accumulator will provide energy for board rake, wing trim, jib trim and rudder rake. Together, the accumulator capacity will be just enough for one tack or gybe. Presumably the grinders will repressurise the accumulators between manoeuvres. Oil demands for jib trim will be minimal. Rudder rake adjustments are allowed while racing, but in practice some teams will probably decide just to set this before each race and then leave it alone.
The planform and sections of the wing are specified by the AC Class Rule, as is the spar structure. Team New Zealand had a cylindrical spar in their AC72 wing in 2013, with a clever twistable leading edge, as on a C-Class cat. The AC Class Rule calls for a rigid D-shaped spar, as on Oracle’s AC72.
The rest of the structure of the wing is up to each team, to accommodate whatever wing trim control system they design. Will the Kiwis have a self-tacking wing, like Oracle, or stick with hydraulic rams to tack the wing, as on their AC72? Remember Dean Barker’s call for ‘hydro, hydro, hydro!’ during the near-capsize in Race 8 when the wing did not tack.
Daggerboard shapes will draw attention and provide interesting topics of discussion for avid AC fans. The head-spinning language of the Protocol concerning limits on daggerboards allows each team to use only four boards in their AC Class yacht. Four modifications of up to 30 per cent of the weight of the board may also be made. Unlimited modifications of up to 10 per cent of the weight are allowed. Reverting a board to a previous shape does not count in the allowed modifications… The logical way to use the four-board quota would be to have a high lift set for light air and a low drag set for medium to heavy air. Teams may also have a total of up to six boards for their AC45X test boats. This is important for two-boat testing, and also in case of breakage.
We can assume that the test-boat boards would fit in the AC Class raceboat. Damage to one of your AC Class boards could effectively end your chances. A recent Protocol change allows two
CURREY ARCHIVE/PPL
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