The rocket from Lake Geneva that tames physics
Imagine a 47-foot monohull with 200 m2 of upwind canvas, a 4-metre draught and a beam of almost 9 metres. These are almost the exact dimensions of the K2, the evolution of the Luthi 10.90 Katana.
Text: Quentin Mayerat
The boat’s destiny is simple: to win the major races on Lake Geneva in real time. After a victorious Bol d’Or Mirabaud and GenĂšve-Rolle-GenĂšve, it’s already a done deal. Faced with the unchallenged domination of the BOM by Hungary’s Libera Raffica, Philippe de Weck and his sons, Micha and Alex, dreamed of coming up with a new concept to put an end to this hegemony. To achieve this, they brought together a trio of top architects: Olivier Mousselon of Mer Forte, the British yard Fiber Mechanics for the composites, and the Luthi shipyard for assembly.
Weight obsession
11 crew aboard, 8 of them on trapezes, abseiling on imposing ladders. The new “bolide lĂ©manique” has only one obsession at the origin of its specifications: to increase its righting moment.
Without claiming to defy the laws of physics, it accepts its principles and converts them into speed.
Weighing in at 1.9 tonnes – fully equipped – this featherweight
has a 95 m2 mainsail and a 650 kg canting keel. Thanks to its well-placed weights, it sails faster than the wind. During our test run, we observed upwind speeds
1 to 1.5 knots faster than the actual wind, in 7 knots of wind. A true architectural feat, the K2 pushes the limits of structural stress. Lighter than a Toucan, this 47-footer is surprisingly wise and stable. “We wanted our boat to be self-righting in the event of desalination, and to be able to be moored in a harbor berth, which is not the case with our direct competitor, Raffica,” explains Philippe de Weck. This is a major advantage, particularly when it comes to enabling a crew made up of numerous amateurs to train on a regular basis. At the time of our visit, the crew had only sailed for the tenth time, which goes to show the key role played by the learning phase on this type of support. For several weeks now, a wealth of data has been collected to build empirical polar charts of the boat. Filled with load sensors, every element of the K2 is monitored to measure all stresses on the structure. The sailing modes and crossovers between the various sails are carefully scrutinized by the professionals sailing on board, notably North Sails sailmaker Michel Vaucher and project manager Jean-Pierre de Siebenthal.
Key idea
“I wanted to bring something new to the world of sailing, confides Philippe de Weck. So I imagined a system of DSS-type foils placed at the level of the ladders.” Indeed, each ladder is fitted with imposing foils, three meters from the center of buoyancy, designed to increase the ship’s righting moment, rather than make it fly.
This 100% archimedean boat could even claim to increase its speed under certain points of sail by 1 to 2 knots thanks to this avant-garde idea. The system still needs to be tested and made reliable, bearing in mind that each of these appendages generates a considerable vertical thrust force on the ladders! With or without its foils, the K2 has undoubtedly
the potential to dominate the Lake Geneva monohull scene for some time to come, unless other enthusiasts in search of a slightly mad architectural project aim to steal the show.