During the last Vendée Globe race, HBK was involved in the Advens for Cybersecurity project, which involved developing and installing optical strain gages on the foils of a boat.
These foils are special ‘wings’ placed under the ship’s hull, composed of a shaft (the longest, typically straight part that goes in and out of the hull), a bearing plane (usually curved) and a tip (a straight, vertical part). As the boat gains speed, the hull rests on the lower part of the foils, which raises it up, so it has less resistance to water and increases speed. The foils are most effective when sailing on reaching (side wind) and can only be used when sailing conditions are relatively calm. Depending on these different factors - and to further optimise the boat's performance – there’s also a mechanism which allows the foils to be retracted into the hull.
The use of foils in offshore racing is recent; they were used for the first time in the 2016 Vendée Globe (the race takes place every four years). Their effectiveness was quickly felt - with the first four boats to arrive at the finish, having been equipped with them - but the technique showed some weaknesses. Since then, the designers have worked to improve both performance and reliability.
The Vendée Globe – a single-handed, non-stop yacht race around the world, lasting for a period of several months – has garnered attention far beyond the world of sailing, due to the courageous skippers, who will be tackling the gruelling, three-month course without any assistance.
During this time, they’ll face extreme weather conditions, rough seas (particularly in the Pacific and Antarctic oceans) and the constant dangers associated with solo sailing. As such, the Vendée Globe is not just an adventure, but an undertaking that requires robust, high-performance boats, that can cope with being constantly pushed to their limits - and sometimes beyond.
The yachts lining up in this competition are packed with high-tech equipment, including sensors which are vital for monitoring a boat’s performance. Test and measurement expert, HBK, which has a reputation for manufacturing high-end sensors and acquisition systems that can withstand extreme environmental conditions, was approached to assist with equipping the vessels using optical strain gauges.
This project was quickly finalised, enabling the boat to launch in September 2019 - eight weeks before the start of the Transat Jacques Vabre. After a few tests, it was lined up for the race. In spite of a failure - linked to the automatic pilot jacks - shortly after the start, which forced a four hour stopover in Cherbourg, Advens for Cybersecurity proved to be very efficient and finished in an admirable fifth place. This comeback is due to strong averages; in one day alone, the yacht covered 521 miles in 24 hours at an average speed of 22.30 knots.
The International Monohull Open Class Association (IMOCA) was the company responsible for designing and preparing the IMOCA Advens for Cybersecurity for the last Vendée Globe, with Thomas Ruyant as skipper.
Its Technical Director, Laurent Bourgues says: "Foils have become an essential element of performance. Today, it is no exaggeration to say that the boat is being built around the foils, rather than the other way around.”
"As for the foils, we are still in a learning phase, as they are constantly evolving, particularly in their shape and dimensions. The validation of the technical choices, design data and behaviour when pushed to their limits, is conducted whilst at sea," continues Laurent.
Due to a lack of time - and also money (a single foil costs approximately 150,000 euros), it is not possible to develop and test prototypes in the laboratory. "For these reasons, we have decided to instrument the foils and record the measurement data. This helps the skipper ensure the boat does not go beyond its limits and we can perform an analysis afterwards, correlating results with other data, such as wind, sea conditions, boat speed, etc," adds Laurent.
"The foils obviously played an important role in achieving this performance. Thanks to the sensors and the acquisition system, the skipper was able to use them optimally, without exceeding the limits," explains Laurent Bourgues.
Thomas Ruyant finished the Vendée Globe 2020 – 21 in 6th place. He arrived at the final destination on January 28, 2021 at 4:42:01 am, with a race time of 80d 15h 22m 01s.
As he finished, many of his competitors were still on their way. See results