A Keller 21Y pressure sensor is at the heart of an hydraulic system powering the tilting keel of skipper Isabelle Joschke’s IMOCA sailing boat, which set out from France in the Vendée Globe ‘20-‘21 race around the Antarctic. This article describes the role of the Keller sensor, which is available in South Africa from Instrotech.
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Sailing has existed as a means of transport for millennia and the spirit of sportsmanship is as old as humanity itself. This combination has given rise to some interesting sports, such as regattas.
At the Vendée Globe ‘20-‘21, for example, a non-stop, round-the-world regatta that takes place every four years, a total of 167 solo sailors started on the Clipper route. The route begins in Les Sables-d’Olonne, a town on the Atlantic in western France, and travels over the Atlantic Ocean to the Cape of Good Hope, South Africa. The route then travels clockwise around the Antarctic via Cape Leeuwin - the most south-westerly point on the Australian continent - over to Cape Horn, Tierra del Fuego, southern Chile, and then back to Les Sables-d’Olonne in France.
Entrants navigated 44 000 km between November 2020 and February 2021. Regatta rules allow participants to moor with an anchor, but not at a dock or next to another boat. Besides that, they receive no other external assistance, excluding weather updates or route information. Only if the participants encounter a problem early on, are they permitted to return to the beginning for repairs and start again. The restart must, however, be within 10 days of the official start.
Skipper Isabelle Joschke
The French-German skipper, Isabelle Joschke, set sail in this challenging race in 2020/2021 in her IMOCA boat, the MACSF. IMOCA boats can be fitted with a canting or tiltable keel. The main performance benefit of this tiltable keel is that, when the keel is angled to the side that is facing the wind (windward), the tilt of the boat is reduced. In case of a possible capsize, the boat can be righted again by tipping the keel to its maximum extent.
Since 2014, canting keels have been mandatory in sailing races. The French company Hydroem delivers assembly kits for IMOCA boats, which are fitted with this type of keel.
The keel is activated using an hydraulic cylinder built into the floor of the boat and connected to the keel. A distributor that contains the electrical valves needed for controlling the hydraulic pressure sits between the hydraulic system components – an electric motor; a hydraulic pump and an oil reservoir – and the hydraulic cylinder.
Keller 21Y Specifications
Accuracy: +0,5% FS
Total error band 1,5% FS @ -10 – 80 °C
Pressure range: 0 - 2,5 to 0 - 1 000 bar
A key component of this system is the KELLER 21Y pressure sensor that is connected to the distributor and used to measure the pressure acting on the keel cylinder.
Through the system, the boat’s skipper can influence the keel directly using a control box to activate the distributor and power the keel, either to stabilise the boat or to save energy by making the keel sink down using a ‘release’ button.
Unfortunately, skipper Isabelle Joschke was forced to withdraw on the 62nd day of the race due to technical problems. Even correct use of the KELLER sensors was unable to prevent this. At the time, she was lying in eleventh place and the leading woman in the Vendée Globe race. Despite difficulties, Isabelle Joschke delivered a noteworthy racing performance.
She was driven by determination and mental strength as she was only one of six women who took part in 2020/2021 race.
Her next opportunity will be in 2024.