This paper considers way-point manoeuvering in three degrees of freedom (surge, sway and yaw). A line-of-sight motivated control law that globally /spl kappa/-exponentially stabilizes an underactuated ship is derived using output redefinition and cascaded systems theory. The control law development is based on a general nonlinear ship model with surge propeller force and rudder moment as control inputs. Simulation results on a full scale model of a supply vessel are presented.