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Ac­tu­a­tors. Ac­cu­mu­la­tors. Foils. Wings. Flaps. Rake. Twist. Cam­ber. In­vert. No, we’re not dis­cussing terms re­lated to the lat­est of­fer­ings from Boe­ing air­craft. In­stead, wel­come to an in­tro­duc­tory glos­sary to the parts and pro­ce­dures re­lated to the winged wind ma­chines that will be em­ployed this month in rac­ing for the 35th Amer­ica’s Cup (see “The Amer­ica’s Cup Lifts Off,” page 18). You re­ally can’t call them yachts. Mar­vels of en­gi­neer­ing is much more ap­pro­pri­ate.

No mat­ter what you think of the cur­rent state of the Cup — and while we all love Ber­muda, I, for one, still can’t fully rec­on­cile why the event is be­ing held there — you have to hand it to the creators of the 50-foot Amer­ica’s Cup Class cata­ma­rans that have been de­vel­oped for the rac­ing. The sail­ing world has never seen any­thing quite like them.

Hy­dro­foil­ing cata­ma­rans are not new to the event; the last Amer­ica’s Cup se­ries, in San Francisco in 2013, was con­tested aboard 72-foot cats with foil­ing ca­pa­bil­i­ties. In what was largely a cost­sav­ing mea­sure, for this go-round the de­fender, Or­a­cle Team USA, stip­u­lated that the rac­ing would be con­ducted on smaller boats with six-man crews. The hulls — which fly above the waves and there­fore spend most of their time out of the wa­ter — would be one-de­sign boats, mean­ing they are es­sen­tially the same for all six com­pet­ing syn­di­cates. But each team’s in-house de­sign team was granted the lib­erty to de­velop its own wing sails, L-shaped foils (or dag­ger­boards) and T-shaped rud­ders, the items that re­ally de­fine per­for­mance any­way.

Those of us who have raced big boats or watched Cup races back when they were sailed on mono­hulls are fa­mil­iar with the large dudes wind­ing the han­dles of the so-called cof­fee-grinder winches, sheet­ing home the head­sails in up­wind tack­ing du­els. Well, the big boys are back, and so are their han­dles, but both are serv­ing a de­cid­edly dif­fer­ent pur­pose. In the most ba­sic sense, the grinders are hu­man pis­tons, or ac­tu­a­tors, that pro­vide juice to what are known as hy­draulic ac­cu­mu­la­tors, or gas cham­bers, which get pumped up to the rel­a­tive pres­sure of a scuba-div­ing tank. This stored hy­draulic power, through a se­ries of rams, pumps, valves and cir­cuits, pro­vides the elec­tric­ity to raise or lower, or change the an­gle of at­tack, of the dag­ger­boards and rud­ders, and to con­trol the wing sail, a three-part air­borne foil that works sur­pris­ingly like an air­plane wing. Are you still with me? Be­cause th­ese new cats can pretty much sail the en­tire course on their foils — even through tacks and jibes — the power re­quire­ments dur­ing the roughly 20-minute races are vast, as the loads and the an­gles of at­tack for the var­i­ous mov­ing parts are con­stantly chang­ing. This means the four grinders on each boat are for­ever spin­ning the han­dles. In­ter­est­ingly, since legs are in­her­ently stronger than arms, the crew aboard Emi­rates Team New Zealand has opted for bi­cy­cle-style pedestal sta­tions for its quar­tet of ac­tu­a­tors. The Ki­wis al­ways seem to bring some­thing fresh and dif­fer­ent to the Amer­ica’s Cup party, and it will be fas­ci­nat­ing to see if their un­usual ap­proach will prove to be an in­no­va­tive game-changer.

Mean­while, as the four grinders con­tin­u­ously top off the fig­u­ra­tive tank, the two re­main­ing crew­men — the wing trim­mer/tac­ti­cian and the skip­per/helms­man — are ac­tively sail­ing the boat. It’s not a stretch at all to call the driver the pi­lot, for he is es­sen­tially in com­mand of a fly­ing ma­chine.

As the boat gets un­der­way and builds speed, it’s the helms­man’s job to ad­just the pitch of the lee­ward dag­ger­board; once its an­gle is high enough to gen­er­ate the lift re­quired to break the hulls free from the wa­ter’s sur­face, the boat tran­si­tions into full foil­ing mode, reach­ing speeds in ex­cess of 30 knots in a de­cent breeze. At that point, as the old Aussie say­ing goes, it’s all on for young and old.

Like the dag­ger­boards, the rud­ders must also con­stantly be ad­justed or canted to con­trib­ute to the lift re­quired to keep ev­ery­thing fly­ing. Si­mul­ta­ne­ously, the wing trim­mer re­mains busy ad­just­ing the solid three-part wing — think of the trail­ing flaps on an air­plane’s wing — to fine-tune its cam­ber and twist, and in­vert it dur­ing tacks and jibes. Oh, and just to add an ex­tra de­gree of dif­fi­culty, he needs to pay at­ten­tion to what’s hap­pen­ing on the race­course with re­gard to the com­pe­ti­tion, and come up with tac­tics and strat­egy as the race quickly un­folds.

It should make for some great tele­vi­sion, which is the point of the ex­er­cise this time around. Crashes may oc­cur, crew­men could be swept into the drink. Think NAS­CAR on the high seas. One thing above all else is cer­tain: It won’t be your grand­daddy’s Amer­ica’s Cup.

Herb Mccormick is CW’S ex­ec­u­tive ed­i­tor.

An Amer­ica’s Cup Class cata­ma­ran in full foil­ing mode is a sight to be seen.

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