Optimising the Vertigo Design
A new sailing yacht designed by Philippe Briand, is being built by Alloy Yachts under the aegis of project manager Andrew Senn. The yacht will be launched in December 2010. She is the largest yacht ever designed and built by both architect and shipyard. The first drawings outlined an overall length of 61 m. Subsequently, the evolution of the design led to an increase in size resulting in 67m length o.a.
The challenge facing the designer was to design a yacht that was large but ‘sensitive to sail’, which explains her modern hull lines. Philippe Briand Ltd reports that she is the first sailing yacht of her size to have an almost vertical bow. This feature allows for a greater waterline length, thus making for a considerable improvement in speed both under sail and engine power. With an air clearance restricted to 68m (for access to the Suez Canal) and a draft restriction of 5m (increased to 9.10 m by a daggerboard extension), the designer was particularly concerned with enhancing efficiency of the sail plan and keel.
A Ketch rig was the only suitable option. Mainsail and mizzen sail include roaches. More surface area of the sails is exposed up where the wind velocity is greater than it is at the proximity of the water. This led to having sails developing a larger driving force than that of conventional triangular sails. Therefore runners are used in instead of permanent backstays, made possible via the technology of mast builders Southern Spars.
Under sail she is expected to reach speeds of almost 20 knots in a reach with a true wind speed of 20 knots. Under engine power the yacht can reach a maximum speed of 17 knots and maintain a cruising speed of 12 knots with an estimated range of over 4000 nm. Accommodation is designed by Christian Liaigre.