Hull Shape
The hulls show extremely little rocker, very flat cross sections, a high prismatic coefficient, and an upside-down bow shape with the widest beam at waterline level. In light conditions the boat is wave piercing, whereas in stronger winds the crew places their weight further backwards and the boat starts – even upwind – to plane. In contrast to boats with traditional V-shaped cross sections, the boat stabilises itself at higher speed due to dynamic lift, hence, reducing pitching to previously unknown low levels. Less pitching leads to a more regular airflow around the rig – especially in the upper part – and hence increases the efficiency of the rig. The same concept was also applied to the floats of Franck Cammas’ new 60-ft trimaran Groupama-2, for which Martin Fischer was a member of the design team. During tests in the largest water tunnel in Europe (Val de Reuil, 600 metres long) it was confirmed that this hull shape not only leads to less pitching but also reduces hull drag substantially. Those tests were carried out not only on flat water, but also with waves of different height and frequency. Another innovation is the double-chime stern of the hulls. This somehow bizarre shape forces the water to detach from the hull at a well defined point and thus leads to a smaller stern wave which finally leads to less drag.
