In November, the same month that the American electorate voted for a 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 49 feet long, these mostly-one-design yachts will be much the same as and much different from the AC45’s 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 control.

When the AC45’s 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 in order 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 only be used 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 set by the AC Class Rule, as is the spar structure. ETNZ had a cylindrical spar in their AC72 wing, with a twistable leading edge, like a C Class cat. The AC Class Rule calls for a rigid D-shaped spar, like 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 like 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% of the weight of the board may be made. Unlimited modifications of up to 10% 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 up to six boards total 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 race boat. Damage to one of your AC Class boards could effectively end your chances. A recent Protocol change allows two “replacement” boards in case of damage to an AC Class board. I wish I could write that more succinctly for you, but my head is still spinning from puzzling through the Protocol.

Oracle, SoftBank Team Japan and Artemis Racing have been sailing together in Bermuda for months, getting to know the local conditions well. Side by side speed tests and practice races have allowed them to measure their progress. Land Rover BAR joined them in December. All these teams will have a test boat to sail against their race boat. Groupama Team France and Emirates Team New Zealand will move to Bermuda in 2017 and will be at a distinct disadvantage: the Protocol does not allow teams to sail or test their AC Class yachts with each other. With the smallest budgets, both the French and the Kiwis have said that they will convert their existing test boats to AC Class compliance (by swapping out the hulls). With only one boat, and the prohibition on coordinating testing with a competitor, they will get a more limited reading on their relative performance. Interestingly, if the AC Commercial Commissioner had announced testing periods last May, as called for by the Protocol, the French and the Kiwis would not be at such a disadvantage. Conspiracy theorists might see something sinister here, but this was probably an oversight.

And, what is to become of those AC45’s? They will be carefully measured and then raced in the Red Bull Youth America’s Cup. After that they are likely to be used again for the World Series leading to the 2019 America’s Cup. The AC45 is dead, long live the AC45.