The measuring in of both Taihoro and Rita for the 37th America’s Cup match was completed on Wednesday and both teams have now declared their equipment and are unable to change from this point onwards.
Ineos Britannia has had no time to test and fit any new equipment. It would have been an extremely high-risk strategy to leave faster kit back in the shed and potentially lose to Luna Rossa Prada Pirelli in the Challenger finals and not even make it to the big dance. So Rita is likely locked into the same set-up used last week and probably going as fast as she can already.
Team NZ, on the other hand, have had the luxury of holding back their best until now. They have revealed a number of visible changes to the boat compared to what they sailed with during the round-robin series over a month ago.
The most obvious of these is the fitting of an entire new rudder and elevator (the horizontal foil that sits on the bottom of the vertical rudder). It looks radical. It is certainly the most extreme in terms of how narrow it is front to back below the top metre.
Right next to the hull the rudder is wide and clearly designed to provide the ability to turn and control the yacht when it is not foiling. However, below this top part the rudder is tiny.
Given how frequently we have heard helms say “I’ve lost the rudder” in the racing to date and the challenge associated with controlling these foiling beasts in a large sea-state, this looks like a high-risk approach from the Kiwis. However, just because a rudder is small does not mean it suffers from less control. The opposite may actually be the case.
A loss of control of the rudder in a foiling yacht is almost always caused by ventilation. That is, when turning the yacht, air is sucked down from the surface along the low-pressure side of the rudder and it consequently loses hydrodynamic flow and its grip on the water. The end result is the driver loses control in a way analogous to a race car driver skidding out around a corner when the tyres lose grip on the race-track surface.
There is no way that Emirates Team NZ has not done their homework on this. They must be confident that this extreme rudder is not only a gain in straight-line speed, but also does not expose them to a high risk of ventilation and loss of steerage.
The second visible change is to the main foils. These are critical aspects for any foiling yacht and both Taihoro and Rita have the smallest area foils of any of the AC75s in this edition of the America’s Cup. Smaller area generally means lower drag which translates into faster straight-line speed. The trade-off is less lift at low speeds and less glide through manoeuvres.
The most noticeably interesting feature of Team New Zealand’s foils is that they have a slight forward sweep on their leading edge and a strong curvature on their trailing edge. The Brits’ foils are not dissimilar but not as radical in their design as the Kiwis.
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These differences likely give an advantage to Team NZ at low boat speeds where they can stay on the foils and glide for longer than the Brits who will probably be more vulnerable to falling off the foils. If this is the case, this difference is a key tactical weapon the Kiwis can exploit in the pre-start. Forcing the Brits to get slow, especially in light winds by being the leeward boat in the final run to the start line and/or turning back to the line early thereby creating a need to slow down to avoid starting early and being handed a penalty will be powerful for Burling and co.
There is no doubt that the Kiwis will have brand new sails on for this Cup match. The sails they used in the round-robins looked tired. Because the sails are what generate the power that makes the yachts fly new crisp sails are always a gain in speed over older tired ones.
The other observable change to Taihoro is a clean-up and improvement of the fairings on the hull and rig. For example, there appears to be a new fairing covering the mainsail traveller. These are small matters, but any time you can create less drag it is a good gain in speed, even if a small one.
In summary, do I expect Taihoro to be faster than she was during the round-robin racing a month ago? Absolutely. Will the speed gain be more than the clear improvements the Brits have made? Not sure, but my inclination is yes, particularly if the winds are lighter in strength.
The Louis Vuitton Challenger finals were an anomaly in terms of Barcelona’s wind conditions in so far as they were much windier than any other of the series including the Preliminary Regatta, the round-robins and the semifinals. This favoured the Brits, who have good pace when it’s windy.
The forecast for the first two days (four races scheduled) of the America’s Cup itself is for light winds of under 12 knots. This scenario means that it is much riskier to be aggressive in the pre-start. Falling off the foils is a race-loser and both teams will prioritise minimising manoeuvres and staying up and flying.
The Kiwis will go in with confidence in the changes they have made and an expectation of a speed advantage. In the end, this will negate the advantage the Brits have with regards to more racing over the past month.
It’s a long series with potentially 13 races (first to seven wins take the Cup) and as a result, eventually, the fastest boat will prevail. Races 1 and 2 will give us a good read on which of the two teams has developed the fastest package. All sailing fans will be watching carefully.
