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.