Geant's secret rudder


The 60ft tris are now flying their leeward floats. Designer Marc van Peteghem explains how
We have all seen the dramatic photos of the experimental French foiler L'Hydroptere - she has recently been moored in Southampton's Ocean Village on standby to make a record attempt. Not to be outdone as the fastest most extreme ocean racers afloat, the 60ft trimaran teams have been spending many hours developing their foil technology over the last months. Most of the modern tris now have curved foils in their floats that are retractible (to prevent drag in light conditions) and have unusual hooks and spades in their tips. The previous generation of foils were enough to prevent the leeward float from digging in. It was interesting to witness how cleanly the new tris went through the water at the start of the Transat Jacques Vabre last year, compared to the older ones which would send plumbs of spray flying back from the leeward bow - more dramatic, but less efficient. The latest generation of foils has proved so effective that at certain speeds the 60ft tris are now beginning to lift their leeward floats clear of the water - like L'Hydroptere. This was witnessed at the Zeebrugge trimaran grand prix at the weekend where for the first time air could be seen beneath Groupama's leeward float. On the reaching dog legs she was hitting speeds of up to 37 knots in 20-25 knots of breeze. So the 60ft tris are now on the verge of becoming fully airborne with all three hulls out of the water and therefore they have less drag and should go ever faster - in short a significant technological advance for the class. But there are some downsides. "Now there is a problem of balance," confirms Marc van Peteghem one half of the design team that created both Groupama and Michel Desjoyeaux's new Geantand was

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