Mastering the balancing act: how SailGP’s Flight Controllers are changing the game

Jonathan Turner
Jonathan Turner
February 14, 2023

What makes a world-class flight controller in SailGP? Well, the truth is, we’re still finding out.

The best Flight Controller displays the steady hands of an Olympic archer, combined with the analytical processing power of a chess grandmaster and the reflexes of a pro gamer. Oh, and not to mention, nerves of steel.

But the truth is that the advent of super-fast, high-performance foiling boats like SailGP’s F50 catamaran has heralded a whole new era of sailors with the skills, smarts and reaction times required to race them.

And forget your traditional view of a sailor: these athletes look more like jet pilots than your typical sea-farer.

A new type of sailor

Although the pace of the racing has ratcheted up many levels from the traditional ‘displacement’ race boat designs that pushed their hulls through the water rather than flying above it, most of the job roles on an F50 – helmsman, wing trimmer, strategist, and grinder – are familiar (if highly-updated) versions of those on traditional classes.

There is, however, one F50 role – that of flight controller – which is utterly brand new to yacht racing.

On-board image of the F50 flight controller 

As the person largely responsible for coaxing the 50-foot catamaran out of the water – and keeping it there – the job of flight controller comes with tons of responsibility and, perhaps, more than its fair share of stress

So, what does the F50 flight controller role entail – and what kind of person is best suited for the job? We sat down with the Denmark SailGP Team presented by Rockwool flight controller Rasmus Køstner to get some answers.

The art of flight

The first time Rasmus saw footage of an F50 in flight he knew instantly he wanted to be involved in SailGP. So, when he got the call from skipper Nicolai Sehested to join the Danish team, there was no hint of hesitation.

“I have always been driven by the desire to develop and to sail the fastest boats and to learn new stuff. When I saw the F50 on the water for the first time I thought it was really amazing.”

Prior to SailGP, Rasmus’ successful career as a professional sailor spanned grand prix yachting’s top tier events, including the World Match Racing Tour, America’s Cup, The Ocean Race around the world, RC44, and the Extreme Sailing Series.

Denmark SailGP Team presented by Rockwool flight controller Rasmus Køstner

Despite all that experience, he says nothing he had done before could really prepare him to take on the flight controller role aboard an foiling catamaran that can reach speeds approaching 100 km/h, powered only by the wind.

When asked what characteristics he possesses that have enabled him to become expert at flying the F50 in the space of just two years, Rasmus told us that, in the beginning, aside from a burning desire to learn something new, he had no special skills that he believes lent themselves to mastering the art of flight.

“It was a new position in sailing and when I started it I didn't have a clue what I was going to do. The first part of it was just trying to learn as much as possible right from the off. That started from day one in New Zealand when the first couple of goes at foiling we had was being towed around on the platform with just a pair of foils.”

Since then, the 45-year-old Danish sailor has been learning on the job and has accumulated a massive cache of specialist knowledge and skills along the way.

Breaking down a flight controller’s responsibilities to fundamentals, Rasmus says the job is principally about balancing the amount of lift being created from the boat’s foils by adjusting the rake, and thereby changing the angle of attack of the lower horizontal section.

“Turning the flight controls allows me to change the angle that the daggerboard has in the water and that’s what gives us more or less lift. Beyond that there are a lot of buttons that take care of all the actions necessary when we are tacking (changing direction by turning the front of the boat through the wind) or gybing (turning the back of the boat through the wind).

The Denmark F50 'flyiing' over the water.

“For those manoeuvres (when the weight of the boat is transferred from one foil to another) there is a choreographed sequence of things that need to happen: you need the ‘new’ board coming down and the ‘old’ board coming up, and also the rudders are changing position too.”

In between tacks and gybes Rasmus focuses principally on the boat’s ‘ride height’ – literally the distance the hulls fly above the water. A screen on the flight control dashboard gives him a digital readout, but the Dane prefers to use his own eyes to gauge how high or low he is flying the boat.

“I look forward, to watch how high the forward part of the boat is flying above the water, because that relates to how high the foils and rudders are in the water. You try to look as far forward as you can because things are happening so quickly that if you are not reacting to things you see up ahead of you then you are reacting too slow.”

How high is too high?

Ride height on an F50 ranges from 1.1 to 1.24 metres and has a huge effect on boatspeed. Put simply, the higher you fly, the faster you go.

But, flight control on a SailGP racecourse is not simply about who can fly the highest. The complex lead up to a tack or gybe manoeuvre, or a tight boat-on-boat situation, may require driver Sehested to call for a lower, slower mode.

“The ride height is pretty much the booster function of the boat,” Rasmus explains. “I can turn the boost on with a really high ride height, but then there is a chance that Nicolai or Tom (Johnson – wing trimmer) might lose control.

“So, you need to manage it a little bit, but if I don’t hear anything from anybody then I am going to be pushing for maximum speed, and that means maximum ride height. I would say that during a race I am pushing as hard as I can 90 percent of the time.:

Denmark SailGP team pushing the F50 for maximum speed and maximum ride height.

Just how hard he pushes the ride height limits depends largely on whether the boat is on an upwind (true wind from ahead) or faster downwind (true wind from behind) section of the racecourse and the surface sea state.

“Trying to fly at 1.25 m downwind means you would have just 65 cm of foil and about 40cm of rudder in the water. In any waves it wouldn’t take much for the foils to be on the water, not in it, and that’s when you can crash.”

A transformation like no other

The extreme speeds of the boats on the SailGP circuit contrast sharply with what were once considered high-performance race boats.

Looking back even just a few years to his professional sailing career prior to SailGP, Rasmus says the transformation has been so large as to effectively make it another sport.

“The speeds we are doing now are three times what we were doing in the Valencia America’s Cup in 2007. Some of the things that were 100 percent right to do in that event are now 100 percent wrong to do in SailGP.

“You don’t see this sort of transformation in any other sport. It would be like Formula 1 cars doing 1,00 kilometres per hour down the straight or tennis players at Wimbledon serving at 750 km/h.”

Although now fully acclimated to SailGP’s breathtaking speeds, Rasmus describes flying an F50 at its limit as part of a fully-synched six-person crew as ‘a truly amazing experience’.

“The boat is going so fast that you can’t think about how you want to do something, or what might go wrong – you just have to react instantly and do the right thing. There are definitely some ‘Zen moments’ coming into play when you are sailing these boats at the absolute limit.”

Sailing vocabulary

  • Foils - Foils are 'ski-like structures' mounted below the hull of the catamaran. When moved through the water, they generate lift helping the F50 to fly.
  • Upwind - Sailing the boat into the direction of the wind.
  • Downwind - Sailing the boat with the direction of the wind.
  • Hulls - the main body of a ship or other vessel, including the bottom, sides, and deck.
  • Rake - the lean of the mast forward and aft. Changes in rake change the balance of the helm.
  • Daggerboard - a board that slides vertically through the keel of a sailboat to reduce sideways movement (balancing the boat).
  • Rudders - part of the steering apparatus of a boat or ship that is fastened outside the hull, usually at the stern.

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