RECON LOG: EMIRATES TEAM NEW ZEALAND’S ‘TAIHORO’ REVEALS SUBTLE CHANGES
Much anticipation down at the Wynyard Point base of Emirates Team New Zealand in Auckland today as their re-vamped AC75 ‘Taihoro’ rolled out of the shed with every intention of beginning training for the Louis Vuitton 38th America’s Cup. First launches in the cycle are the Kiwis' calling-card, but Mother Nature today wasn’t playing ball with a tropical front dramatically changing the plans for the day.
The call was made to cancel training and the boat went back into the shed at 11.22am (NZL time) after a 9am roll-out. The recon teams were on the ground and with the boat on its high-cradle, the striking 'Napoli' adorned Naples-blue foil arms and foils naturally were the focus - and there are some subtle differences from when we last saw Taihoro winning the 37th America’s Cup back in Barcelona in October 2024.
In interview with the recon team, Dan Bernasconi, the Chief Designer for ETNZ was quizzed about weight distribution in the new AC75 electro-set-up that has removed four cyclors from the sailing team, added in a sailor to have five inputting sailors and a guest racer and replaced the powerhouse cyclors with limited battery power. Dan commented “we’ve taken weight out of the foils” and the most visible example of this is to compare the 2024 Taihoro foil arm fairings with today’s.
What we see most starkly is a reduction in the volume of what was nicknamed the ‘foil spike’ in Barcelona. This was considered to be an area of ballast and with a focus on lower wind-speed take-off – the AC38 Protocol has a range today of 6.5 knots to 23 knots of raceable conditions – it is clear that ETNZ are looking at that performance profile. The new Taihoro no longer has the forward protruding inverse anvil shape that featured so heavily in Barcelona.
Where this falls under the AC75 Class Rules is around the ‘foil arm fairings’ in rule 13.6 stating that: “Foil arm fairings shall not be capable of transmitting any significant bending, shear or torsional loads between the foil wing and the foil arm.” On Taihoro today we see a big reduction in volume in this area, and it’s something to look out for as the team progresses through early sea trials and commissioning of the new set-up. The anvils were a very late addition to the set-up in Barcelona.
Furthermore, for the first time (we believe) we are seeing pitot tubes attached to the front of Taihoro’s foil bulb. These are non-permanent and would of course be taken off for racing but it’s worth looking at what pitot tubes are used for in the America’s Cup. A direct take from the aviation industry, pitot tubes are primarily used to measure the precise water speed of the boat (speed through water) rather than speed over ground, which is essential for controlling the flight and performance of the yacht at varying speeds. This is crucial for calculating the actual hydrodynamic forces on the foils, especially considering the tidal currents that are sometimes present during training.
The data from pitot tubes helps the crew understand when the boat is about to reach, or is maintaining, the necessary take-off speed and these tubes collect critical data that both the crew and the analytics teams on the chase-boats use to monitor performance in real-time, similar to Formula 1 telemetry. Pitot tubes are rumoured to offer much higher accuracy in measuring the yacht’s speed through water, preventing significant errors that can be up to 20% in test data caused by relying solely on GPS in high tidal flow such as ETNZ might experience in Auckland.
Components for the 38th America’s Cup are strictly regulated and limited for cost-saving purposes. The teams all had four foil arms in the last cycle and are mandated to re-use those for this cycle. Only minor changes can be made and we most likely will not see any new foil development on the AC75s until much nearer the racing in Naples.
Looking at Taihoro’s foils in 2024 versus 2026 suggests that the team are running the same foils as used in the last Match, with the clever fairing that from the top makes the foil appear like a single piece of linear carbon when there are in fact two controllable flaps (see from underneath). The slight anhedral nature of the tips at both end create an almost perfect 'gull wing' in profile. The recon teams will be getting detailed photos of this when Taihoro first sails.
Looking for the differences that will decide the Louis Vuitton 38th America’s Cup are going to be a lesson in detail. The recon teams are on it.
Magnus Wheatley