The Cyclors of American Magic

The AC75s of the America's Cup are power-hungry beasts. The human input required for sustained foiling and maneuvers on demand is a critical piece of the design puzzle.
Cooper Dressler and John Croom
American Magic’s power team is currently a mix of sailors like Cooper Dressler (left) and high-output athletes like cyclist John Croom (right). Katrina Zoe ­Norbom/American Magic

American Magic’s AC75 Patriot glides through the water near Pensacola, Florida, and as it picks up speed with the day’s favorable winds, the imposing dark hull rises from the water and begins to plane on its hydrofoils. Crouched near the bow, pedaling furiously, John Croom is lashed by spray. His earpiece crackles with chatter from the rest of the crew. He has watched videos of America’s Cup boats. He’s logged hundreds of hours of training on land. But this is his first time—his first time on any sailboat.

“Still to this day, that’s one of the most euphoric moments I’ve ever had in my career,” Croom says. “Getting the opportunity to sail, and then just feeling that actual takeoff and being on the foils was something super special. That was the day I fell in love with it.”

While some of sailing’s traditionalists bristle at the inclusion of cyclors in lieu of grinders on America’s Cup boats, there’s no turning back now. The technology will be found on every boat in the 2024 America’s Cup.

This novel power-delivery method has opened the door for newcomers like Croom to hop aboard, like throwing a ­drivers-ed student into a Formula 1. It has also led to a revolution in the way America’s Cup teams recruit talent, hone their physiological training, and use cycling know-how to power the AC75’s hydraulic controls.

“We’re finding that cyclors bring much more power to the table,” says Ben Day, American Magic’s performance lead. “Cycling uses much bigger muscle groups; therefore, they can produce more power than arm grinders. And with the new AC75 regulations of reducing crew numbers (eight sailors total), we need to find that power in other ways. So, most teams are looking at cyclors at this stage. Glutes, quads and hamstrings can produce more explosive power and more power for a longer sustained period.”

Day is another example of someone outside the sailing establishment who quickly entered American Magic’s inner circle. Day had a 12-year career as a professional cyclist, racing primarily in North America. Once he retired from racing, the Australian started Day by Day Coaching out of his adopted hometown of Boulder, Colorado.

Not surprisingly, Day and American Magic looked to the cycling world to find athletes to fill their “power teams.” The team had preliminary conversations with Kiel Reijnen, a professional rider who spent six years in cycling’s WorldTour, racing the sport’s premier events, such as the Tour of Spain, Tour of Flanders, and multiple UCI World Championships.

“We focused on leg-­dominant power sports, with similar activities that would fit the needs for racing on the boat,” says Day of the recruitment process. “We have taken time to examine a whole list of athletes that might fit the bill, and then have reached out to consider interest.”

It wasn’t as simple as assembling a bench of top cyclists. The rule book states the combined weight of the eight-person crew must be between 680 and 700 kilograms. Split evenly, that means each person should be between 85 and 87.5 kilograms. Reijnen weighs 65 kilograms. It’s rare to find a pro cyclist that weighs more than 80 kilograms because power-to-weight ratio in cycling rules all. Cyclists can control both variables in the power-to-weight equation. Training can boost power output, measured in watts. They can also lose weight to improve their power-to-weight ratio. Naturally, any given rider has limits for both variables. The best professionals are extremely efficient in their power production and astonishingly lean. It would be a tall order for someone like Reijnen to gain 20 kilograms without compromising their power output.

Croom is uniquely suited to the challenge, having found cycling late in life after playing football in his younger years and at times weighing close to 136 kilograms. Though he slimmed down to about 90, he’d never be suited for road cycling. Track cycling, on the other hand, was a good fit. Since track events are held on a flat, 250-meter track, weight can be sacrificed at the expense of raw power.

Ashton Lambie is another hopeful on American Magic’s power team who never quite fit cycling’s mold. This mustachioed Nebraskan holds the record for the fastest ride across the state of Kansas. He’s also the only human to ever ride the 4 km track pursuit event in under four minutes.

The riders you might see on television at the Tour de France are not going to be aboard an AC75 in Barcelona. Similarly, the athletes who have been recruited to pedal the cyclors aren’t ready to ride on day one, despite their extensive backgrounds in cycling. Intense training is underway to prepare them for the demands of an America’s Cup race.

“There are periods where we spend time focusing more on endurance or strength development,” Day says. “At other times, we’re working more around the high-intensity phases.”

While American Magic has been mum about the specifics of the training and the AC75’s power demands, Croom has posted many of his recent workouts and training rides on Strava, an online activity tracker.

Croom has done extensive endurance work, already logging weekly rides longer than 80 miles in January. He’s also been completing viciously intense interval workouts to build his body’s tolerance for maximum efforts. For example, he was able to hold 371 watts for 20 minutes in one such workout. Simply a statistic, right? I’ve been racing bikes for the last 25 years, and at my best, I can hold 302 watts for 20 minutes. Someone without training or experience would do well to maintain just half of Croom’s wattage.

While the training and performance of these new crewmembers are opaque, the technical details of the AC75 are practically impenetrable. American Magic’s spokespeople and crew did not answer specific questions about how the hydraulic power system works, but what we do know is that the boat has a hydraulic accumulator tank, which stores pressure generated by the cyclors. The crew uses a hydraulic actuator to convert the tank’s pressure into force, which in turn powers the boat’s controls. Any time the boat needs to tack, jibe or simply trim a sail, power is needed.

Sources indicate that the hydraulic accumulator results in a very unusual feel at the pedals for the power team. It’s also believed that as the tank gets full, the effort to add more pressure to the accumulator becomes harder.

“We can change the different inputs to the system,” James Wright, of the American Magic power team, told the America’s Cup Recon Unit, which monitors and reports on the team’s developments. “The different power demands necessitate different inputs from us on our side. The system kind of auto-adjusts depending on the demands from the sails and, of course, what we can give it.”

It’s easy to imagine how the team might strategize its efforts, given the intensity of a 20- to 30-minute America’s Cup race and the essentially limitless power demands of the boat. They might attempt to keep the tank as low as possible with steady, moderate pedaling, and then fill it as fast as possible with maximum effort ahead of a demanding maneuver like a tack. Perhaps some of the four riders would be specifically reserved for all-out efforts to fill the tank on demand, while others would ride steadily to feed power to minor adjustments.

Whatever the strategy, it is clear that the entire crew needs to be in lock-step during a race. “When we talk about the sailing team, we consider the power team part of a sailing team; they have to work in cohesion,” Day says. “The afterguard will request efforts from the guys as they trim the boat, and they’ll learn what they can deliver in terms of power. And the guys will give it their all to deliver what’s asked of them. So, there must be solid cohesion between the two groups; ultimately, we are one team.”

Clearly, the sailors, engineers and coaches are working furiously to optimize the use of the cyclors. There is another area of the sport that has some catching up to do, and that is World Cycling’s anti-doping controls. Even the casual cycling fan is aware that performance-­enhancing drugs have long tarnished the sport’s reputation. Given the massive physiological demands placed on the AC75’s power team, the sport’s governing body, World Sailing, would be wise to heed the lessons of cycling’s past.

In the wake of a major doping scandal about 10 years ago, cycling began rigorously testing athletes out of competition because it was found riders could achieve huge performance gains by doping for training and then cleaning up in time for in-competition controls at races. It stands to reason that this is a major liability for the America’s Cup, given the amount of run-up that the teams have to train for the 2024 event.

Although World Sailing conducted 186 in-competition tests between 2020 and 2022, including anti-doping ­controls at the last America’s Cup, it did not conduct any out-of-­competition controls during those three years. To ramp up efforts for the 2024 Cup, World Sailing brought on Vasi Naidoo as its director of legal and governance. Naidoo has experience with anti-doping efforts at the Olympics and Commonwealth Games, and she served on the Ethics Commission at the UCI, cycling’s international governing body. World Sailing confirmed that there will be out-of-­competition anti-doping tests in 2023, and the testing will include America’s Cup athletes.

Fortunately, on the whole, the interplay between cycling and sailing—two unlikely ­bedfellows—has resulted in a fascinating exchange of technology and science. “The transition to cyclors allows a tech-forward, applied-­sciences sport to pull in a completely separate sport and borrow technology from it,” says Reijnen, who himself is an accomplished sailor, having finished the WA360 event sailed out of Port Townsend, Washington, in 2021. “What does sailing borrow from cycling, but what does cycling then borrow from sailing?”

Even at the person-to-person level, this exchange of information and experiences has been rapid and, in fact, quite cordial.

“The coolest part about being part of this team is that I came into this group of sailors so new and so green,” Croom says. “And they were super-­welcoming, understanding, and trying to get me to learn as quickly as possible. Like, any questions I had, there was no such thing as a dumb question, and that was something special.”