l'Hydroptere heads for US in quest for new offshore speed record marks
by Thomas Lesage on 23 May 2012
l'Hydroptère DCNS, the French¨ flying trimaran¨ of Alain Thébault, has just completed her last trials off the La Ciotat (France)coast and is ready to leave for Los Angeles where she will attempt her first offshore record.
Les 5 corsaires de l’Hydroptere pour le record du monde du Pacifique. Jacques vincent, Jean Le Cam, Yves Parlier, Alain Thebault et Luc Alphan .
Francis Demange www.hydroptere.com
They were waiting for this moment for weeks. The five crew members of l'Hydroptère DCNS could test the new configuration of the flying trimaran in a strong mistral Mediterranean. All the weekend, under the watchful eyes of their technical team, Alain Thébault, Jean Le Cam, Yves Parlier, Jacques Vincent and Luc Alphand made several runs, sailing between 20 and 45 knots according to the angles to the wind.
For the first evaluation, some results are promising.
The works dedicated to the boat's versatility are highly positive. The trimaran is stable in the waves. Technically as mentally, this data is vital. 'l’Hydroptère is a nervous machine, taking off with prodigious accelerations, but she is also a relatively small boat compared to others. To fly over the Pacific swell at 35 knots on a 60 feet boat of 7 tons, we do not adopt the same strategy as with the power and behaviour of a 130 feet boat of 23 tons. The record is above all mental and it is important to know that the boat beneath us is reliable, and stands the waves', said Jean Le Cam.
To meet this challenge, the profiles of the foils were rebuilt this winter at the shipyard B& B at La Trinité Sur Mer in the configuration they had before the speed records. The angle of attack’s changes on the submerged wings, when the boat sails up or down a wave will be with no loss of stability.
'Between 2006 and 2009, at the time of the absolute speed records, we designed profiles to limit the effects of cavitation on the behaviour and performance of the boat beyond 50 knots but they are less tolerant to variations in the angle of attack because these records take place on very quiet water surfaces.
This year, it's a little bit the contrary, the profiles are designed to operate in a 'bumpy field' but with a maximum speed reduced to 50 knots, 'said Philippe Perrier, one of the 'papés' of the team.
Concerning the sails, the improvements now allow to sail at 140 ° to the wind with a speed of about 30 knots with 20 knots of wind. 'We are excited, there are still some works to strengthen the support of the flying jib boom and optimize the curvature of the headsails but the key elements are there and the boat will be able to sail downwind efficiently,' said Jacques Vincent, co-skipper of the boat.
Another core issue: The control of the rear foil. So far, the adjustment of the rear foil was done manually and was used simply to optimize the boat’s average behaviour according to the sea conditions. The hundreds of hours of sailing recorded, analyzed and compared to modelling by the technical team have identified a method for controlling the rear foil to significantly absorb the rolling and pitching of the boat and thus improve her behaviour and her performance offshore.
The technical team of engineers charged DCNS with the task of installing the system on the boat to achieve this control. The experience of DCNS in this field will also be utilized to consider other modes of control that might require new sensors. In this perspective height sensors above the water have been installed around the boat and the connectivity of the entire system was synchronized with the inertial unit.
'These are problems that occur on the SSBN (submarine ballistic missiles) or other ships that we built,' says Damien Laval, an engineer at DCNS. It remains the most delicate stage of the operation: Putting everything in harmony. 'The task is not simple and on topics that are so much complex, it is better to remain humble. The optimization phases can be long on l’Hydroptère. We are facing the unknown but I am a high-tech peasant and I love when it's tough 'jokes Alain Thébault, designer and skipper of l’Hydroptère.
l’Hydroptère DCNS will sail a few more days in the bay of La Ciotat for a series of final tests. She will then be loaded onto a cargo ship to join Los Angeles where she will be positioned to wait for the best weather conditions for her record attempt to Honolulu. The five Corsairs will soon be able to answer the call of the sea.
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