By now, we at SAIL had been hoping to be able to publish photos of the new AC50s that will be taking part in the Louis Vuitton Elimination Series, which begins May 26, and the 35th America’s Cup set to take place in late June. However, it was not to be, thanks to a recently devised 28-day blackout period, which currently has all the AC50s under wraps in Bermuda with planned launch dates in the next couple of weeks. The enforced ban reportedly came as a concession to ETNZ, which has had trouble keeping pace since the lack of a World Series regatta in Auckland killed its chance at receiving any government funding. The details of the process—in true Cup tradition—have been somewhat opaque.
That doesn’t mean, though, that Cup fans haven’t still had plenty to talk about in terms of boat design or engineering, thanks to the nature of the design rules governing the AC50s and the extensive use of souped-up, “turbo” AC45s as test beds for the various different technologies the syndicates hope will provide them with a winning edge.
In contrast to Cup cycles past, actual hull design is largely pre-set—and doesn’t really matter since the hulls will be airborne from start to finish—however, the field remains wide open in terms of internal wing structures, lifting foils, fairings, cockpit design, and the combination of hydraulics and the all-important control systems needed to make sure these incredibly complicated 50-knot machines don’t just work right but remain in one piece.
The teams also need to figure how best to arrange the ergonomics for a six-person crew, as opposed to the five-person crews sailing the AC45s over the past two years of the America’s Cup World Series.
“The 45 test boats are basically a copy—just 5ft shorter—of what the new race boat will be,” says Oracle Team USA skipper Jimmy Spithill. “Ideally you take pieces from the test boat and then plug them into the America’s Cup Class boat. But it is a development game, and we’ll be constantly evolving right up to the final race.”
“According to the protocol, the maximum size available for a test boat is the lower portion of an AC45 hull. You could do a smaller test boat, but obviously, everybody has chosen to go for the most relevant platform,” says Artemis Racing’s David Tyler, of his team’s two-boat development efforts.
To this end, some of the more notable modifications seen aboard the various turbo AC45s slicing their way across Bermuda’s Great Sound include flared topsides to accommodate cockpits housing the necessary grinders for powering each boat’s hydraulics; twin wheels (as opposed to the tillers found on a standard AC45); fairings on the crossbeams; vaguely foil-like protrusions extending beneath the mast steps that are apparently structural but may also enhance the efficiency of the wings overhead; and of course, various different daggerboards.
Something not so apparent is the dozens (maybe hundreds) of load sensors on the boats and the hydraulics and/or mechanical systems being used to manipulate things like daggerboard orientation and wing shape. In today’s Cup world—where a team’s ability to instantaneously and precisely control its foils can mean the gain (or loss) of multiple boat lengths in the blink of an eye—these “nuts and bolts” matters have become the technological equivalent of yesteryear’s winged keels.
Indeed, so data driven have today’s AC boats become, that aboard the Oracle turbos even the sailors’ heart rates are being measured as they relate to the amount of grinding torque they are able to generate.
Strange days! Although there can be little doubt the resulting boats set to do battle this spring will be a sight to behold.
March 2017
