Two fuel tanks are situated on opposite sides of the central longitudinal axis of a boat. An inclinometer generates electric signals indicating the inclination of the boat about its longitudinal axis. The two tanks are connected hydraulically by at least one pipe with which a pump is associated. An electronic processing and control unit acquires and processes the signals emitted by the inclinometer and operates the pump, depending on said signals, so as to transfer fuel from one tank to another in order to reduce the inclination of the boat.