Left: Charlie Dalin and Yann Eliès on the Verdier-designed Apivia demonstrate why the foiling Imocas are, in the words of fellow skipper Sam Davies, too fast to be sailed by a human being. Sam’s conclusion is based upon the almost complete absence of forward visibility at these speeds as much as the required response time for changes in course, flying attitude and altitude simply being beyond the ability of a human to cope with for more than a few minutes at a time. Reaching out to the Fastnet Rock in last year’s race, Sam and co-skipper Paul Meilhat on Initiatives Coeur were sailing at a steady 30kt+ in only medium breeze. As soon as there is anything of a sea state today’s Imocas can match the performance of the then outrageously fast Orma trimarans like a pensive Michel Desjoyeaux’s Géant (above) – seen here preparing for the 2006 Route du Rhum
and no less than the instinctive way a good helmsman always tries to race his yacht. Let’s start again. A ‘classic’ pilot is able
Cup the next step is to make it possible to fly across the oceans also under autopilot. The new pilots are destined too to break
out of the small niche of shorthanded ocean racing because, until now forbidden outside solo or double-handed events, the autopilot will become authorised in more and more crewed races, including RORC events which opened the doors at the start of 2020. Indeed, pilots may well be permitted for the Imoca class in next year’s The Ocean Race. It is not a simple debate. The genius of these new-generation
autopilots is that they no longer follow a single pre-set parameter (a heading or wind angle), but several set targets simul- taneously: more precisely, a main para - meter (typically the true wind angle) but influenced directly by other factors includ- ing apparent wind speed and angle or heel. The pilot is told: ‘I am asking you to
steer the boat at a certain actual wind angle but I will allow you to deviate slightly from this set point, as long as you follow the apparent wind variations as closely as possible and/or maintain the heel within a certain range.’ This is no more
to follow a compass heading on a direct course. In the right conditions it can do this very precisely – as long as the boat is well balanced and cleverly trimmed to the desired course. But life becomes much harder and the course less precise when the wind varies in strength or direction (with a crew, one would probably constantly adjust the sail and/or ballast settings to maintain course; racing solo the tempta- tion would be rather to leave the sheets but make small changes of course with your handheld pilot control). To go upwind it is preferable to assign
the classic pilot a wind angle. But if the boat stumbles into a wave and slows down the pilot is unable to understand that it is necessary to trim slightly to accelerate again and get back to course. To avoid this situation the skipper sets the pilot to sail a more open angle than the boat’s best VMG angle: for example, under pilot you may sail at 29 or 30° from the apparent wind, where the helmsman’s target would be 26 or 27°. Not only is the course less good, but the pilot is also unable to take advantage of opportunities to luff above the target course in gusts. The third scenario is downwind sailing
in VMG mode. Here the classic pilot is traditionally set in ‘true wind’ (TWA) mode because the variations in apparent wind angle due to accelerations in the waves are too great to expect stable and
efficient steering under AWA conditions. But it doesn’t know how to drive ‘en relance’, in other words by luffing to create speed when the wind dies and then bearing off as the wind builds again or a wave offers you the opportunity for a nice surf. The latest versions of the top-of-the-
range pilots for ‘customer’ sailors benefit from improvements that partially elimi- nate some of the above-mentioned disad- vantages. Both the H5000 from B&G and the HR from NKE have a relatively similar mode (Gust Mode) which allows the head- ing to be modified when the boat is over- pressed. Then, set in a Polar mode, the pilot targets the best VMG angles as defined by the boat’s polars, an angle that therefore varies with the actual wind speed. NKE also now offers an interesting surfing function, which adjusts for the acceleration on the wave. All of this works, and is a good step
forward from the popular systems of a few years ago. But ask any of the top skippers who are already using them, and they will tell you that the new systems developed by two specialist French companies have rocketed the entire concept of autopiloting into a new dimension. According to the winner of the 2004-2005 Vendée Globe, Vincent Riou, who is using the system being developed my Madintec,
the
machine knows how to react to heeling upwind in the same way as a human sitting at the helm is guided by his sensory inputs. In this case, the pilot is assigned a true wind angle (TWA) parameter that is
SEAHORSE 47
JEAN-MARIE LIOT/ALEA/APIVIA
BENOIT STICHELBAUT/ALEA
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