A hydrodyanmic interaction between the ship and the bank wall is well known as "bank effects" which consist of the suction force and the bow-outward moment. The safe distance to the bank wall, in which the ship course can be maintained within 5 degrees of counter rudder angle, is summarised as safety margins of the fairway for ships in the Next Generation Fairway Design Standard (2007). The results were based on theoretical calculations and numerical simulations. On the other hand, many captive model tests were carried out to investigate the ship-bank interaction but almost of them estimated only the hydrodynamic delivatives and the ship-handliing limits were estimated by solving the motion equation of ship maneouvrability. The direct measurement of the counter rudder angle that can offset the ship-bank interaction has never been carried out so far. In this study, model experiments were conducted to find the ship-handling limits under the ship-bank interaction forces. Using the circulating water channel, the oblique angle of the model ship and the counter rudder angle were adjusted to find the equilibrium point in vicinity of the bank wall. The measured value were compared with the theoretical value of the Next Generation Fairway Design Standard (2007). The results pointed out some possibility of underestimation for the safety margins of the fairway.
