Return of Geronimo

James Boyd looks at what has been done to de Kersauson's maxi-tri since her return from her Jules Verne attempt

Friday June 7th 2002, Author: James Boyd, Location: France
Olivier de Kersauson's giant Cap Gemini Ernst & Young and Schneider Electric sponsored trimaran Geronimo was put back into the water in Brest harbour today, following repair work to solve the rudder problems she experienced on her Jules Verne Trophy attempt earlier this year.

De Kersauson brought in two hydrodynamicists from the French naval school in Brest and specialist Mick Kermarec to look at Geronimo's rudder problem. During the Jules Verne attempt the rudder is believed to have been suffering from both cavitation and ventilation problems. The cause appears to be that the rudder area isn't big enough and its construction wasn't man enough to deal with the enormous loads experienced from its 1.85sqm blade (this compared to around 1.1sqm for the maxi cat blades). The result has been that the rudder has been deflecting.

In the period since Geronimo has been out of the water at Chantier Latitude in Brest, the carbon fibre rudder has been removed and the aft side of the stock beefed up with uni-directional carbon fibres. The blade itself could perhaps be larger, but this would only increase the loadings and possibly make the problem worse.

The obvious solution is to fit three rudders, one in each hull as the 60ft trimarans have had now for more than a decade for this very reason a fix which also ensures one rudder is always in the water even if two are airborne... However de Kersauson, who probably ranks as the most experienced trimaran sailor in the world and therefore should know, is keen not to go to three rudders partly because it is too complex but also because there is three times the likelihood of catching one on some flotsam.

De Kersauson's team have been running computer simulations to test the hydrodynamics and structure of the beefed up rudder and it is said to be much improved.

While the boat has been out of the water the bottom of the beam fairings has also been strengthened, not because they are broken but as a preventative measure - the fairings seem to have been a weak spot with the big Ollier cats in particular. The team led by Olivier Bordeaux have also been carrying out minor repair work to the mast.

Geronimo, like Orange and Maiden 2, is expected to do carrying out a programme of records in Europe this year and it is rumoured that there may be an interesting three (or four if Mr Fossett comes to play) maxi-multihull line up to make an attempt on the Round Britain record late this summer.

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