A hull structure, especially for recreational vessels, includes at least one insulated bottom element section or moveable bottom element displaceable laterally by means of projecting actuators from a position adhering to the hull and preferably recessed into a respective shape, to at least one position projecting outside of the hull, with respect to which members for widening the deck project therewith in synchronism with the at least one displaced hull section or displaced moveable bottom element and vice versa.