Chalmers University of Technology
SSPA received a special visit this week as two Swedish sailing teams came by to test their foils, for the second time around. The main focus is on a special measurement method developed by SSPA and Chalmers - which has already paid off for the sailing teams.
"We've taken a big step forward in our sailing this year and now we have our eyes set on the Olympics in Paris in 2024 and after that the Olympics in Los Angeles in 2028," says Ida Svensson, Swedish national sailor in the Olympic class NACRA 17.
We found ourselves at SSPA, the now RISE-owned maritime research and ship testing facility located on the Chalmers campus. From the outside, a fairly inconspicuous brick building. But on the inside - among huge tanks, workshop halls and laboratories - marine research at highest level is taking place.
Here we're met by Arash Eslamdoost, Associate Professor in applied hydrodynamics at Chalmers, and Laura Marimon Giovannetti, researcher and project manager at SSPA. Together, they've developed a unique method to simulate and predict with great precision how hydrofoils behave in the water under a range of different conditions. Their research is of great interest to the shipping industry, which with the use of further developed hydrofoils can benefit electric vessels also over longer distances - while at the same time making the shipping industry significantly greener. How? "As the hydrofoils, like wings, lift up the boat hull and make the boat "fly" over the water surface, the resistance is reduced by as much as 80 %. Less drag means longer range for a battery fueled ship," Arash explains.
Speed increase of up to 50%
It also means that the speed of the boat can increase significantly. A phenomenon that sailing has already discovered. In recent years, hydrofoiling technology has revolutionized the sport, where the sailors today reach much higher speeds than they used to. The research that takes place at SSPA and Chalmers is hence of great interest to the competitive sailing community. And Laura's interest in hydrofoils is far from a coincidence.
"I've previously competed in both the Italian and British national sailing teams and today I'm working as a technical advisor for the Swedish Olympic Committee and coach the Swedish teams," she says. In her role, Laura technically advises the Swedish national sailing team in four different classes. One of the teams consists of sailors Ida Svensson and Marcus Dackhammar and today they are visiting the research facility to, with Laura's help, make advanced measurements on their hydrofoils in the hope of optimizing their sailing.
For three years, the team has competed together in the Olympic class NACRA 17, that is, a 17-foot-long catamaran equipped with foils.
"I'm the helmsman and Marcus is the one pulling the ropes," says Ida.
The Olympic class has been in development for the last few years and has now completely switched to using foils. And there's no doubt that the hydrofoils make a difference:
"Previously, we only foiled downwind, but with the new rudder system introduced after Tokyo 2020, we are now able to fly upwind also, so going up against the wind, which means an increase in speed from about 10 - 11 knots to about 15 knots. In other words, an almost 50 % speed increase," Marcus explains.
The quest for the right degree of stiffness
Above all, it's the hydrofoil stiffness that the team is interested in measuring at SSPA's facility. Ida and Marcus buy the foils from the boat manufacturer NACRA, but in order to find the hydrofoils with the best characteristics for sailing, they need to combine testing in the lab with testing in real life.
"We're here to measure the stiffness of the rudders and the daggerboards, which are a big part of making the boat go faster," Marcus explains. And Ida fills in:
"The faster we go, the more important it becomes to have the right equipment. NACRA is a catamaran, and if we know in which side we sail faster, then we can find out which degree of stiffness results in the fastest speed."
In the center of attention for today's foil testing is a measurement method that makes it possible to study the foils' stiffness at a detailed level and see how they're affected if, for example, the load or speed increases or when the positioning of the foil changes.
In the lab, the foils are "set in place" into a device and weights are attached to increase the load. Three advanced cameras document even the smallest changes in the hydrofoil and send the data directly to a computer where Marcus, Ida and Laura can see the results in real time, both in numbers and in 3D illustration.
It's a fine balancing act. The stiffer the hydrofoil, the higher the boat "flies" and the speed increases. But if the boat flies too high, the foils start to ventilate, which in turn may result in abrupt speed loss, slamming and risk of injury.
"We've tested a range of foils that have had a difference of 15% in stiffness and we can see that it's a factor that makes a difference. Then of course it's difficult to rule out other factors, such as waves, water temperature or how we behave on the boat, that is the human factor, which also might influence the sailing," Marcus explains.
"We've taken a big step forward"
Marcus and Ida have already noticed that the measurement in the lab pays off in their sailing. It's not the team's first visit to the facility:
"We were here last spring and tested the foils we had then. Now, we've bought new gear that we'd like to test. During this year, we've taken a big step forward in our sailing and now our eyes are set on the Olympics in Paris 2024 and after that the Olympics 2028 in Los Angeles," says Ida Svensson.
Although the tests that can be carried out at SSPA may be considered somewhat unique, it's most likely that other nations also conduct similar tests on their foils. But exactly how is shrouded in obscurity.
"There's nowhere else we can get this data from. Thanks to Laura, we can connect the research done here to reality. It's very likely that our competitors from other countries also do tests, but no one wants to share what technology they use or what the results look like," says Ida.
After Ida and Marcus have completed their tests, a longer training trip to Lanzarote awaits this winter, where they will also have the opportunity to compare today's measurement results with how the foils perform in the water. The competition season starts in April and then the Olympics in Paris 2024 looms.
"Right now, we're in between 12th and 18th place in the world in our class. There are 19 countries participating in the Olympics, so first we have to get a place in the selection," Marcus explains.
And if all goes as planned, Laura and her hydrofoil research will follow the team for years to come.
"I will continue to help the Swedish sailing team until the Olympics in Paris in 2024 and hopefully also until the following Olympics in Los Angeles in 2028," says Laura.
Text: Lovisa Håkansson
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