North Sails NEWS


Key Developments from an Evening with Burns Fallow

📸 Emirates Team New Zealand

Time is closing in on the 36th America’s Cup which commences in Auckland on the 6th of March 2021, and with the recent launch of Emirates Team New Zealand’s (ETNZ) second boat, competition is heating up between the teams. North Sails and ETNZ were delighted to host an evening of discussions at the ETNZ base, kicked off by an exclusive virtual video from North Sails President, Ken Read in Newport, Rhode Island, announcing his plans to come to New Zealand to commentate for the duration of the America’s Cup.

North Sails Auckland General Manager, Richard Bicknell, introduced North Sails designer and speaker for the evening, Burns Fallow. As one of the most sought-after sail designers in the world and a colleague of Bicknell’s for 20 years, Fallow started working for North Sails in 1988 and has since been heavily involved in the Whitbread, Volvo Ocean Race, and the America’s Cup, with this cycle marking his sixth Cup; a special milestone to reach.

From Grand Prix to Superyacht sails, Fallow holds an international presence in sailmaking and takes great pride in designing sails for more local boats as well. He also spent time mentoring younger designers across the globe, namely Gautier Sergent in 1999 who is now the chief sail designer for INEOS TEAM UK.

We have compiled our key takeaways from the in-depth discussions had by Burns Fallow and teammate Rob Salthouse:

1. The AC75’s are the fastest monohulls ever to sail upwind:

Reaching speeds of 20 knots velocity made good (VMG) upwind, the AC75 marks the evolution of sailing over the last 20 years. No other sport in the world has seen improvement like this over such a short time. “The AC75 Class Rule is the bible that we have to abide by in terms of specifications of the yacht,’’ Fallow explains. “The rules can sometimes get in the way of great ideas, but in this class, unlike the last couple of Cup cycles, it has been left reasonably ‘open-ended’ to let different teams express themselves from a design point of view.’’

2. Why do we want boats to fly?

It is a reduction of drag. Carrying a hull through the water when sailing upwind or downwind, the boat is going to travel slower than if you can just rely on the foils to balance all of the aero-forces.

📸 Emirates Team New Zealand

3. Key Design Areas:

Hull: With an overall length of 75-feet (including bowsprit), the four teams weigh within 1 kg of each other. The foils and cant-axis are fixed, and so is the displacement. All of these factors are tightly policed.

Foil Wings: Sitting at the bottom of the foil, the wings are an active area of development and a highly critical part of the design process. The tab on the back of the foils is controlled manually to make the boat fly high or low.

Rudder: The AC75’s have a single rudder on the centerline with a horizontal wing (elevator) at the back. The elevator is an actively controlled surface and thus has limits in width, height, and length to help maintain flight.

Rigs: The rigs are only just longer than the boat at 26.5m compared with the AC72, which had a 40m mast length. The AC72 and AC75 weigh about the same with a similar righting moment, but in place of a keel, the AC75 has two foil arms, so a taller mast would affect the stability of the boat when off the foil. This can make the transition period tricky when trying to get the boat to take off, so requires a lot of management.

Double-skin Mainsail: Large D-Section spar with a pair of mainsails hoisted together to retain traditional concepts of sail design. The double-skin reduces drag by stopping the sails flapping through the tacks and is also very stable through manoeuvers.

4. Racecourse:

Races will start later in the day (~16:00 NZDT) to increase the chances of a good sea breeze developing and also working better for coverage around the world. The pre-start will be between 2.5-3 minutes, starting upwind with a windward leg followed by two or three laps to the finish. The typical race length is expected to be approximately 25 mins.

5. All North Sails teams are using full 3Di inventories:

Fallow comments, “It gives me a huge amount of flexibility as to where I want to put tapes. If I’ve got a problem area in a sail which I spot in the simulations, I can put some tape there. The makeup of the fabric is the same as what we might use for any boats with 3Di sails. The primary difference is the percentage of carbon we might put in relation to the Dyneema from a longevity/toughness point of view. But our sails are built on the same machines, same molds, same design software.’’

6. All the operations and functions of the foils are manual:

There is no ‘follow-the-dot’. Controlling the foils lies all in the hands of the guys onboard who are doing other jobs as well. They’ve got a lot on!

Looking ahead, the four teams have a series of match races over 2-3 days in December (Christmas Cup), followed by the PRADA Cup in January to determine which of the Challenger teams will take on the defender Emirates Team New Zealand. To win the America’s Cup, first, you have to win the PRADA Cup. So now it’s time to sit tight and wait to find out who will take home the oldest trophy in international sport.

📸 Emirates Team New Zealand 
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