Left and above right: it all starts to go wrong for Aethon when a roughly executed gybe sees two flap hinges come apart. But the entire flap then breaks away leaving the team sailing very fast under just a super-high aspect wing. All is well until a big gust at the weather mark where the imbalanced wing now refuses to ease leading to a destructive capsize (top right). 0800 and all is calm… (left)
integration of the platform and trampo- lines into the wing design in the future. This is a very rich vein of development – preliminary studies show that a sealed trampoline combined with a canting rig can increase drive force by up to 30 per cent and provide as much as 150kg of lift. These numbers are large enough to be unbelievable, but they are tantalising. It’s also clear this has to be an integrated design, not something that is cobbled together. The scatter in data points shows that if you get it wrong, it’s worse than doing nothing.
Groupama’s foils and foil controls have advanced from 2013. Co-designer Martin Fisher would share no estimate of how much better, but the proof was clear on the water. The green boat took off in about 5kt of wind and sailed away. If one assumed that Hydros had been ‘just off the pace’ in 2013, the advance has been as much as 20 per cent.
Groupama now control their foil cant angle without changing the depth of the foil and have narrowed and refined the necessary ranges of motion. They can easily repeat settings, and have even intro- duced subtle details like having the wind- ward foil trim nose up when withdrawn to
make it less likely to trip on the top of a wave. Smart stuff. The Hydros foils and controls are pretty much unchanged from 2013. They are much more approximate, using Spectra tackles to control cant angle and angle of attack. Nor- gador started the week with bow-mounted Moth-style wands linked to the angle of attack tackle, but removed this mid-week. The university project Rafale-ETS’s foils were one of the only parts of the boat not built by the team and they were awful. Nevertheless, they did fly on occasion and recorded a top speed north of 27kt. Our own American curved foils did not live up to their promise. We expected that a lower-drag solution that eliminated the foil extending below the windward hull would be faster in light and marginal con- ditions and safer in high wind conditions. Controlling the cant angle by adjusting the extension of the board proved unworkable due to the loads on the head of the board. Further, the process of tacking and gybing was so awkward that any speed advantage we may have enjoyed was lost in the cor- ners. There was just enough performance to suggest that another iteration might yield success, but it is a tough call. Once again, actually learning how to sail with
any of these systems is a large challenge. Some will look at these results and think that there is no way to compete with Groupama. Others will disagree and this article suggests how one has to go about doing it. One needs a good boat and a team that is capable of keeping it sailing day after day. Then one needs to devote enough time to learning the intricacies of sailing the boat to its full potential. Lapses in concentration have always been costly in high-speed sailing, but on foils the losses are amplified.
The good news is that sailing a C-Class catamaran is great fun. The powers that be seem intent on removing development from yachting. The C-Class is one place where we embrace it. Instead of feeling humiliated by the beat-down that Groupama rained on our heads, we are impressed. It is comforting to know that the horizon continues to be far away and that there is lots to learn and discover.
A day at the races
I can only tell you about our first race day. The forecast is for it to blow hard… in Geneva. Where the average wind speed is 5kt, we are going to get 20 building to over 25 by mid-afternoon. Aethon has
SEAHORSE 31
LUKA BARTULOVIC
GILLES MORELLE
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