Effect of the loading conditions on the maneuverability of a container ship

Abstract

A container ship transferring numerous containers must stow them in the proper slots. There are many factors to consider, such as the handling efficiency, stability, and hull strength due to weight distribution. Because the number of cargo containers depends on the shipping market, this can affect the displacement or draft of the hull. Optimizing the trim for improved fuel efficiency is another important consideration these days. Thus, a container ship navigates under various loading conditions in the daily voyage. Although the trim and draft effects on the resistance and propulsive performances are of concern, more research is required on their effect on maneuverability, which is important for the ease of ship control and safe navigation. Therefore, this study aims to determine the trim and draft effects on the container ship's maneuverability by conducting free-running tests to measure the maneuvering motions and captive model tests to clarify the hydrodynamic forces. Each test was under five loading conditions and comparative analysis was performed. Especially, since we found the course stability became better as the shallower draft or larger trim by the stern, the analysis based on computational fluid dynamics was conducted to explain its mechanism. Visualizing the flow velocity and pressure fields around the container ship under different loading conditions, the mechanism is clarified in association with them.