America's Cup: ETNZ's design head Dan Bernasconi explains the key points of the new Rules

INEOS Britannia and Emirates Team NZ - Day 3, Race 6 - 37th America's Cup - October 16, 2024 - Barcelona © Ricardo Pinto / America's Cup

As the anticipation builds and preparation by all teams is quietly ramping up for the upcoming America's Cup, Dan Bernasconi, Head of Design for Emirates Team New Zealand and one of the architects of the third edition of the AC75 Class Rule and Technical Regulations has unveiled some of the key points that will govern the design parameters of the AC75’s that will race in Naples in 2027.

One of the most visible design elements of any America’s Cup is the hull of the AC75, and as Bernasconi outlines, this will be one of the biggest surprises in the new Class Rule, “One really significant change is that we're not going to be building new hulls this time around.”

“By not building new hulls, we’re getting double the value out of the hulls we have already got, which is a large cost saving for the teams, but also a significant environmental saving. One factor in this decision was that the difference in the hulls across teams is more visual than performance-related. Whilst everyone’s hull looks quite different, they are all well optimised aerodynamically, and there is actually not much to choose between them in terms of raw speed. There is much more performance to be gained in the foils, sails and control systems, so those will be the areas of focus this time around.”

Furthermore, by not having to build new hulls, teams will be better prepared in what is now a compressed timeframe in preparation to race in the summer of 2027.

One of the more contentious changes among different teams and followers has been the elimination of cyclors onboard the AC75’s. Human power is being replaced by a standardised battery-powered system, an approach that will ensure uniformity across the boats, with power levels calibrated to performance data from the last America’s Cup that will reward efficiency in power usage.

“Every team will have an identical system to supply power to the systems which control the sails. The standard power system, referred to as the RigEPS (Rig Electrical Power Supply) in the AC75 Class Rules, will mimic the amount of power that the cyclors on the yachts were able to physically generate. There isn’t going to be unlimited power available to the sailors, so the design of efficiency hydraulic systems is crucial, and sailors will need to manage their power use carefully.”

Once the decision was made to replace the four cyclors, this provided the space to add a fifth sailor and a guest racer into the mix. There is now a requirement that at least one of the five crew members is a female sailor.

“It is an exciting dynamic. Whether we will see a female sailor helming, flight controlling, on strategy or tactics or even a new innovative sailing role, I think there will be some variation across the fleet. Everyone will look at the team of sailors they have and try to get everyone in a role that will give them the optimal performance. It will be interesting to see how the teams split the five sailing roles onboard,” said Bernasconi.

“It is very cool that we have managed to continue building the pathway for the best women sailors in the world on to the AC75, especially after the success of the Women’s America’s Cup in Barcelona.”

So where are the performance gains to be found within the Class Rule?

“The racing will definitely be closer in AC38, now in the third generation of this class. The level will be higher and the systems will be more mature. Everyone feels they can still get a lot more out of the boats. There is still a really long way to go in terms of performance gain for teams, making the sails work well across the range, optimising the shape, structure and the hydraulic systems that are used to control them. Also with the foils, there is always that 50 knot barrier which we saw smashed a number of times in Barcelona. It’s the cavitation limit which we are always talking about how you get through that. We know how to design foils that can exceed 50 knots, but it’s harder to translate that to something that can also sail a windward leeward course efficiently.”

In terms of the racing itself, the dynamics are expected to change. With a stronger average wind in Naples than Barcelona, the racing promises to be more competitive than ever.

“Teams are looking forward to fleet racing, and maybe switching up the match racing a bit, so it is going to be a pretty cool event for all of the spectators on land, on boats or watching the global TV broadcast.”

As the teams prepare for the challenges ahead, Bernasconi is excited for the potential of the designs and upcoming races.

"This is the third edition of the AC75 Class Rule, but there are always exciting developments. The teams have the absolute best design and engineering minds available, optimising their yachts within the constraints of the Class Rule as best as they can – and that is why the America’s Cup is the pinnacle of innovation in our sport. There's still so much more to come from the AC75." said Bernasconi emphasising the commitment to continuous improvement and innovation in the sport.

It will be an interesting time once the America’s Cup world starts to see the AC75’s emerge from the sheds once again.