The Study On Rudder Effect Of Low-speed Ships In Shallow

Along with ships to development of large-scale, special-purpose and high-speed, maritime transport and river traffic have become heavier and more crowded, Thus dangerous marine accidents such as collision aground in port area increase greatly and many reasons should be responsible for these accidents, one of the them is that the human factors pay little attention to ship maneuverability. The ability to control ships by rudder has been a long-term issue professionals pay close attention to. Ships'speed is often lowered and restricted in shallow waters. In the circumstance of some certain speed, rudder effect is lost due to stopping propeller. Less theoretical, the very steering speed is mostly relies on the ship experiment. Researches on Satisfied models for simulation and prediction in shallow areas are even less. So the study on rudder effect is of great practical significance.In view of above reasons, this paper adopts MMG model idea and on the basis of mathematical model research in shallow waters, low-speed and large drift angle offered by previous researchers, both of the movement continuity of ships, combining two types of math models, shallow-waters large drift and small angle are built. When creating the models, small drift angle adopts the Kijima model and Yoshimura model goes to the large drift angle. The mixed model was suitable for the entire maneuvering ranges including normal speed, low speed, small and large drift angle and so on. Considering the effect of shallow waters, the conclusions on Yoshimura was adopted.Relying on the above models, this article realizes model simulation with MATLAB. Meantime provided that with no impact made to ship by winds and current, using the ship experiment to confirm this model's accuracy. Navigate in 4 minutes under stopping propeller, full rudder, simulates changes in the course and the rate of course, analyses each factor about rudder effect. At last we can sum up a set of practical conclusions, which can provide references for pilots.