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“Flying boat” dips its wings in Lake Geneva

Hydroptè gets its first taste of Lake Geneva Keystone

A revolutionary Franco-Swiss "flying yacht" project that aims to smash the round-the-world sailing record has started testing on Lake Geneva.

Hydroptè, a prototype catamaran based on the world’s fastest sailboat, was gently lowered into the clear waters near St Sulpice, west of Lausanne, on Friday.

A five-man crew plan to test the new design, materials and boat behaviour over the coming months on Lake Geneva.

The new ten-metre test boat uses the same hydrofoil design as its older sister, the existing 18-metre Hydroptère, which already has several world speed records to her name. In 2008 it became the first sailing boat to break the magic 50-knot (92.6km/h) speed barrier and then topped 100 km/h, travelling at up to 56.3 knots (i.e. 104 km/h).

But Hydroptè is the first-ever hybrid boat, allowing it to fly on its two hydrofoils in medium to high winds and sail as fast as a normal sailboat in calm conditions, explains Alain Thébault, the 46-year-old Breton who is the brains and driving force behind the project.

“It’s a new concept,” he told “Today boats float but our flying boats are the first trying to understand the dynamic stability problems of this new design.”

The Hydroptère, which Thébault started working on in 1987, is based on minimising the friction from the water and waves. With the wind blowing at only 12 knots, the two hulls rise above the water, and the vessel skims the surface of the waves with the tips of her wings.

The two adjustable hydrofoils set at angles on the hulls give the vessel stability and lift, while a retractable tail unit at the rear of each hull act as a rudder.

“When we are at full speed, only 80cm of each foil is in the water, we are 1.5m above the sea and there are only three small points in contact. There is no drag and acceleration is really powerful,” said Thébault.

The boat is also fitted with a retractable central dagger board so it can sail with its foils out of the water when winds are light.

Hydroptè will serve as a model for a future giant catamaran, Hydroptère Maxi. In 2013 Thébault hopes to smash the current 50-day crewed round-the-world record by up to ten days.

“I believe that to be a completely realistic target,” he declared.

Different feel

Jacques Vincent, one of the test navigators, said the boat felt totally different to traditional catamarans.

“All the power is concentrated on a very small area. It’s much sharper, so you feel the vibrations and sideways motion. It makes you feel quite uncomfortable and you need to helm differently. On a normal catamaran the load is spread over the length of each hull and it’s much smoother,” he explained.

Hydroptère’s design team, assisted by scientific advisors from the Federal Institute of Technology in Lausanne (EPFL), has adapted the original configuration of the vessel due to instability at high speed.

“We are trying another design with the front foil aligned with the rear rudder,” said Vincent. “If the boat heels over it will stay aligned and there it controls much better, especially in waves.”

Innovative features

Work on the new prototype started at the beginning of 2009 at the B&B shipyard in La Trinité sur Mer, France, and at Décision SA Ecublens, near Lausanne – both specialists in composite materials.

Décision helped build the America’s Cup yacht Alinghi and the Solar Impulse, Bertrand Piccard’s solar plane.

“To make a flying boat the weight was extremely important,” Décision’s director, Bertrand Cardis, told, adding that in terms of complexity, the boat’s ultra-light carbon-fibre honeycomb structure is closer to the Solar Impulse than Alinghi.

The test boat has a number of other new innovative features.

The front of each floater resembles a “Canadair” flying boat, with a built-in adjustable step that can be raised or lowered up to 15cm, depending on speed and conditions.

When it is flying, this shape allows the boat to touch and bounce off the water without slowing down and air flows through the gap, reducing friction between the hull and the water.

A T-shape foil at the end of each retractable rudder enables the boat to be trimmed accurately to keep it horizontal, preventing the bow from burying in the water and losing speed.

The boat is also equipped with a central electronic unit and 40 sensors record adjustments and stress on the foils, hulls and rigging, as well as providing weather data.

1975: A team of aeronautical engineers, aircraft part manufacturers and sailors convince “father of French yachting” Eric Tabarly of the Hydroptère’s viability, but the project does not materialise.

1987-1992: Alain Thébault builds and adjusts a model on a one-third scale.

October 1, 1994: Hydroptère’s first flight.

2004: installation of the strain absorbers by André Sournat that ensure the structure’s strength.

February 9, 2005: The symbolic cross-Channel record by airman Louis Blériot in 1909 is smashed by Hydroptère in 34 minutes and 24 seconds with an average speed of 33 knots.
In 2005 EPFL President Patrick Aebischer and Geneva banker and sailing enthusiast Thierry Lombard came on board the project.

Hydroptère has held two world records since April 4, 2007: the fastest sailing vessel over one nautical mile with an average speed of 43.09 knots, and the fastest over 500 metres in category D (sail surface area over 27.88 m²) with an average speed of 46.88 knots.

In 2008, in its quest for the absolute sailing speed record, Hydroptère became the first sailing boat to break two symbolic sailing speed barriers: 50-knots and then 100 km/h, reaching a top speed of 56.3 knots (i.e. 104 km/h).

In October 2008 kitesurfer Alexandre Caizergues established the absolute world speed sailing record of 50.57 knots over 500 metres.

French skipper Bruno Peyron broke the crewed round-the-world record on March 16, 2005 when his Orange II catamaran and a crew of 13 completed the 27,000-nautical-mile (50,000 km) circumnavigation in 50 days, 16 hours and 20 minutes.

Frenchman Francis Joyon smashed Ellen MacArthur’s 2005 solo round-the-world record in January 2008 when he finished his circumnavigation in 57 days, 13 hours 34 minutes and six seconds.

While testing the Hydroptè, Thébault hopes to break the speed record on Lake Geneva, which stands at 22 knots.

Next year the team also hope to break the multihull record for the Transpacific Yacht Race from Los Angeles to Hawaii, which stands at 5 days 9 hours 18 minutes 26 seconds.

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SWI - a branch of Swiss Broadcasting Corporation SRG SSR