America's Cup, the last card foil for Luna Rossa

With Ruggero Tita and Vittorio Bissaro both away sailing Nacra 17 ‘s in Palma it was the turn of Jacopo Plazzi, the 49er ace, to partner with Francesco Bruni on the first day back on the water for Luna Rossa Prada Pirelli’s LEQ12 after an extensive ten-day period of maintenance, refit, and upgrade. Immediately out of the shed the newly declared port foil could be seen and offered, perhaps, a distinct clue as to the design direction that the Italians are pursuing.

A slender, refined bulb protruding forward with a long span, very flat wing with a reduced foil flap radius is a refinement of the starboard flat foil that the team have been A/B testing and replaces the slender anhedral that the team were running on the portside throughout March. A thing of beauty, there was additional refinement in the lower foil arm, but the flap arrangement is yet to be captured by the recon team who will be looking closely at this in the coming days. It certainly looks a step-on from the original flat wing now running on starboard and the team were anxious to get straight-line data on this first commissioning day.

In stunning Spring conditions out on the Bay of Cagliari, the Italians had their LEQ12 flying low and fast in the southerly sea breeze that filtered in at 14-16 knots and touched speeds downwind in excess of 45 knots. Even at warp-speed, the LEQ12 looked remarkably stable in flight and highly manoeuvrable and although the day wasn’t about tacks and gybes, the small number that the team executed looked fast. Take-off down-range still required not one but two crew-members to come to the windward side with one sitting in the aft pod whilst the other hung off the shrouds. However, as the breeze came in, this was less of an issue and the Italian LEQ12 popped to flight with ease.

The day was all about early foil evaluation with long runs extracting both the performance and media data that the designers and engineers will be comparing against their computer modelling. Speaking about the process to bring the new foil into commission, design chief Horacio Carabelli commented: “It's a long process, the design of these wings, not only from the hydro point of view but from the manufacturing point of view, it's pretty long. So this month we have worked pretty hard from the engineering point of view and putting things together and today was more a commissioning day for it so we have a lot to learn about it for the next weeks. It’s pretty important that it’s coming along as the ‘last card’ that we have to play on it so pretty happy with today. I think it was very, very, efficient and we got the numbers and expectations. We had all the engineers onboard also taking a look at it, so pretty happy overall.”

When pushed about the design packages that the Italians are using to settle on candidate foils, Horacio added: ‘I mean it’s a full package of software that we have, it's not only VPP you know it's CFD involved and all the systems are pretty complex on these boats and controlling the foil it's also a big part of it so it's a lot of things that we go through and loops to get to the final candidate and get ready and put it in the water so it's a long, long time for the whole process.”

With all the teams now deep into the final stretch of design iterations for the one-build AC75 that they are allowed to build under the rules of the 37th America’s Cup, these are vital days of testing and evaluation. Is Luna Rossa Prada Pirelli indicating that perhaps the anhedral, long span foil is dead? Horacio Carabelli was giving little away saying: “This is a surprise for you in the following months, so I leave it there just for you to have a bit of imagination about what's going to come.”

Intriguing. Will we see flat, slender foils in Barcelona like those of Luna Rossa Prada Pirelli and NYYC American Magic? Will the anhedral long span, single-flap of Emirates Team New Zealand win out? Or will the W-Foil concept being trialled by INEOS Britannia be the concept that proves fastest?

The design race for the America’s Cup is well and truly on.