側壁影響下の操船限界に関する実験的研究-II.- プロペラ推力の影響 -

A hydrodynamic 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 summarized as safety margins of the fairway for ships in the Design Standard for Fairway in Next Generation (2007). The standards were based on theoretical calculations and numerical simulations. The authors carried out the model experiments to find the ship-handling limits under the ship-bank interaction forces and pointed out some estimates to be considered as under-estimated values of the standard. In the previous report, there was also a discussion concerning reliability of the experiments because the model ship was equipped with no propeller. In this study, the method of the experiment was improved in order to realize the actual running condition in vicinity of the bank wall more accurately. The model ship was equipped with a propeller and its rotating speed was adjusted carefully to find the equilibrium point together with the oblique angle and the counter rudder angle. As the results show, it was revealed that the ship speed has little influence to the counter rudder angle but can't be ignored completely. Moreover, there are still some cases in which the actual allowable bank clearance exceeds the estimates of the standard.