In this paper is studied the static and dynamic behaviour of an innovative hull. The hull, called Y-hull, consisting of a hybrid structure between a catamaran and a monohull, was tested in the towing tank at the laboratories of the University of Trieste.

The most distinctive feature is the presence of a central tunnel that affects the back part of the hull. In its forward part, the hull has a geometry similar to conventional hulls with a very marked V shape. This allows to have good directional characteristics and a good seakeeping in rough sea conditions. The aft part has the typical form of multihull with the huge difference that the area affected by the presence of the tunnel lies always below the water plane.

The forms allow to convert, during the motion, a significant rate of the kinetic energy of water in pressure energy on the bottom. This without that the hull presents a positive angle of attack throughout its extension. Part of the energy conversion is delegated to the presence of the central tunnel which leads to a slowdown in its water that it is forced to flow resulting in increased pressure energy. The resulting lift is accompanied by a reduced formation of spray.

The work shows the interesting results of the tests performed in the tank and a series of numerical tests performed with the aim to develop future enhancements. Numerical simulations were carried out in order to understand the distribution of pressure on the bottom. In this way it will be possible to perform appropriate shape optimizations.