The authors tried to conduct a model test as the first step into the investigations on ship maneuverability with side thrusters. The experiments were performed by maneuvering 6 m L_<pp> liner model with an operator directly on board at Kakogawa Model Test Basin, Kawasaki Heavy Industries, Ltd. Tested items were as follows: (1) Short turning test. (2) Approaching a stern-on berth under sternway. (3) Investigation into effects of ship speed. (4) Turning test by combined operation of rudder and side thrusters. As the results, the followings were obtained. Side thrusters give good effects on ship maneuverability in the delicate maneuvers, such as those in approaching to a berth, or in a restricted water. Ship's forward speed affects appreciably on the performance of side thrusters. Turnability recovers after once falling with increase of speed in the case fitted with the bow thruster, while the reverse turning is possibly daveloped in the case of the stern thruster.
