Groupama have declined the invitation to partake of AC36 but their skipper Franck Cammas remains hopeful. Not surprising given their lead in monohull foiling and soft-wing technology, there is plenty of French interest in the new AC75 Cup boat: the head of IRC in France, Jean Sans, has had his calculator out with these early projections of a base boat. Sans suggests a generic 80/20 foil/rudder lift distribution with a lift-off speed of 16kt. Early days…
are well placed to make that decision.’ Then there is talk of the AC75 having
three jibs to suit wind conditions plus a code zero to provide enough horsepower to get the boat foiling in lighter winds. But Cammas observes that if the AC75 is as fast as ETNZ are predicting there will be no need for even this limited sail inventory… ‘You cannot have more sails if you are fast. You have to choose.’ In other words, fast boat = fewer sails; slow boat = more sails. And even with the proposed wider inventory what will the 10-12 crew do? But Simmer reckons that all 12 crew will
be used simply because the sail loads will be huge thanks to the AC75’s high righting moment and, unlike on the AC50, sails will also have to be moved about. Obviously the crew can be set to task on
the grinders/bicycles, as before, but even the larger crew may struggle to maintain the power demand for canting two independent and ballasted T-foils/keels. So it seems likely those twin foils will be canted by electrically driven hydraulic rams as they are on conven- tional canting-keel boats, this power derived from a battery rather than an engine. If it is a one-design battery, then deter-
mining some way of ensuring that boats start racing with the same amount of charge could be a challenge. But it could be a more interesting – and sellable – concept if the power cells were not one-design, if teams were given carte blanche to create power however they want, for example, without using fossil fuels, or by generators using hydrogen cells or other clean hydrocarbons. As mentioned previously, an engine or a
At the time of writing rig height and sail
area remain undecided but, as mentioned in the last issue, the Defender and Challenger of Record are contemplating a hybrid soft- sail-wing arrangement that would wed a wing section spar with a double-luffed, twin-membrane mainsail hanging off its trailing edge. Simmer reckons if they go down this
route they may end up with heavy and light- air sail set-ups, similar to mainsails on the
50 SEAHORSE
Version 5.0 ACC monohulls a decade or more ago. He warns: ‘The difference in the sail area that you need between foiling and non-foiling is huge; and being able to make that transition, even on a windy day, from having enough sail area to manoeuvre and get from displacement to foiling mode – they are going to have to figure that out as they are writing the rule! But I think Dan [Bernasconi, Emirates Team New Zealand Technical Director] and the numerical tools
battery could handle all of the power requirements for trimming sails and appendages, and with computers hooked up to the correct sensors to determine the optimum trim of everything, crew members could be left with precious few roles avail- able. Fortunately there is agreement that having an ‘automatic’ boat such as this would not make for good sport. However, opinion remains divided on the merits of having human hamsters providing power on grinders or bikes, as we saw on the AC50s – a job that seems of little interest to the sailors involved, being effectively just an athletics display for spectators. Cammas isn’t a fan of these grunty crew
roles. He believes the humans onboard should be able to apply their sailing skills, by helming, tactics or trimming, and so on. Simmer agrees:
‘Hopefully the flap
adjustment will be battery-powered, as will the rudder rake, then that just leaves the crew dealing with all the sailing functions. We are in favour of the crew making all the
w
JEAN SANS
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