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America's Cup: ETNZ chief designer Dan Bernasconi reveals all on the AC40

by Justin Chisholm, Cup Insider 4 Jan 08:33 GMT 4 January 2022
AC40 is designed by Emirates Team New Zealand and will be a development of Te Rehutai, the current America's Cup champion. © Emirates Team New Zealand

Justin Chisholm of take an exclusive deep dive look at the new 40-foot one-design foiling monohull concept with Emirates Team New Zealand’s head of design Dan Bernasconi.

One of the most exciting new aspects of the 37th America’s Cup cycle is the introduction of a new America’s Cup class – a scaled down 40-foot foiling monohull version of the AC75 class, known as the AC40.

Sailed by a crew of four, the teams can utilise the AC40 as a training boat for honing match racing skills, and/or a development mule for testing new rig or foil designs.

After being returned to full one design configuration the AC40 fleet will also be used for any preliminary regattas prior to the Challenger Selection Series and the 37thAmerica’s Cup Match – such as America’s Cup World Series events – as well as for the Youth America’s Cup and Women’s America’s Cup.

To find out more about how the AC40 concept came to fruition I booked some time with the man at the centre of it all – Emirates Team New Zealand designer Dan Bernasconi.

Bernasconi told me that the idea of a class of a class of scaled down AC75s that were simpler and easier to sail than the full-size boats was triggered by outside interest in the team’s one off half-scale training boat, the 38-foot Te Kahu, which the Team New Zealand sailors trained on whenever their AC75 was in the shed or in transit.

“Towards the end of the last campaign, in the last two or three months before racing, we were all thinking about what happens next – win or lose,” Bernasconi said.

“We had a few people casually ask about whether we were make the small boat that we had, Te Kahu, into a class. It's a really cool little boat and the sailors loved sailing it and there was quite a lot of interest from from local sailors here [in New Zealand].”

Encouraged by the interest, the team created a mock up of what a potential one design version of Te Kahu might look like, and even got as far as producing a draft marketing brochure.

Then, when work began on the Protocol for the 37th America’s Cup, Bernasconi and his designers revisited the idea.

“I guess it gradually turned into something more concrete and more of a reality as sort of a multipurpose boat for the for teams to use as a training/development boat for the pre-regattas – where it's easier and more practical to transport AC40s around the world to different venues,” Bernasconi said.

“But also to use it as a training boat both match racing and for development when you can swap out components, put your own foils and sails and rig.

“Then for the Youth America's Cup and the Women's America's Cup, it seemed like a great platform for that – and potentially for private owners as well.”

In terms of a design brief for the AC40 Bernasconi said the overriding principle was to make the smaller boat as similar as possible to the AC75.

“It's based on the the new generation of AC 75, rather than the old generation,” he points out.

“So the AC40 is scaled down from an AC75 with a wider span on the foil wings, and without the burden of the largely impractical Code Zero headsail and bow sprit.”

“The geometry is just scaled down,” he said. “The only thing that is really different is that the bow is shorter. That’s because the AC75 is quite a long boat and the forestay is a fair way back from the stem.

“If you take the AC 75 and scale it down not all the way to 40 feet and then shrink the bow so that the forestay comes almost to the stem. [With the AC40,] effectively, we've got a bigger boat into a smaller length. That's really about trying to fit it into a 40-foot container length.

To simplify shipping and reduce costs the AC40 is designed to be transported on its side in an open top 40-foot container or 40-foot a flat rack.

But the task of creating a new design based on the Kiwi’s full-sized America’s Cup-winning boat is a much complicated process than simply scaling back the hull and rig dimensions.

Much of the AC75’s scintillating performance came from the boat’s myriad complex proprietary control systems. Surely the team would want these to remain a closely kept secret from their rivals?

It’s hard not to see the AC40 concept as a sort of reverse Trojan Horse – a gift wrapped package of ETNZ intellectual property delivered directly into the hands of the challenging teams.

“We have had quite dilemmas about how much IP to give away in the boat,” Bernasconi confessed.

Despite understandable nervousness about the risk of giving away too much Bernasconi said the design team had not held back or compromised the potential of the AC40.

The primary goal, he told me, was for the AC40 to be a really cool boat that would take off well and deliver high performance across the wind speed range.”

Bernasconi said there had been some unease about putting all the teams secrets into the new boat. In the end the decision was made to trust that the team would stay ahead of its rivals by continuing to innovate throughout the AC37 cycle.

“As a design team, we are all really excited about the AC40 and we want it to be a success,” he said. “So we are giving it our best shot based on what we know at the moment and we hope that whatever we do give away we are going to improve upon over the next two three years of our with our R&D programme for the next edition to go into our next race boat.”

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