The invention relates to a floating vessel of the type that consists of a floating structure comprising a platform which connects two hulls (2), said hulls (2) being pivot articulated to the platform (1) such that they can move, for example, between at least two pre-determined floating positions. In addition, the hulls are equipped with ballast/deballast means (5, 6, 7, 8A, 8B) and means (11) enabling same to be immobilised in each of the floating positions thereof. The inventive vessel is characterised in that the connecting platform (1) takes the form of a floating element. The vessel is further characterised in that the hulls (2) are moved from a floating position to another position by at least the pump ballast/deballast means (5, 6, 7, 8A, 8B) of the hulls, said means co-operating with the hull-immobilising means (11). According to the invention, the operation of the ballast/deballast means and the immobilising means are controlled by a central unit (4) which uses a series of pre-determined sequences in order to control said means in a simultaneous and/or alternating manner such as to cause the hulls to pivot essentially under the effect of hydrostatic forces.