The Study On The Bow And Astern Thruster' Effect

Along with the development of ships to large-scale, high speed, special-purpose maritime transport and river traffic have become more busy and crowded. Thus risks of marine accidents such as collision,aground in port increase greatly. Ships' speed is lower in restricted waters, and the usage of the thruster can enhance the steering ability of the ship. But until now, the most research is about the bow thruster, little research is about the astern thruster. This paper studies the manoeuvre ability of the ships equipment with bow thruster and the astern thruster.According to Japan MMG's separated modeling theory, the formulas for calculating hull hydrodynamic force, rudder force and propeller force are presented, and the hydrodynamic interaction among them; A integrated shallow water and low speed mathematical model for simulating ship maneuvering with lateral thruster is presented in this paper, and lateral force is added to this mathematical model as well. this paper adopts MMG modeling ideas and provides a math model which combined the Kijima model and Yoshimura model. Considering the effect of shallow water.The study has obtained the following conclusion. Maneuvering efficiency of the lateral thruster is mainly related to velocity. The bow thruster force will decrease along with the increase of the velocity in the shallow water, and the astern thruster is different from the bow thruster. The efficiency of the thruster and the gyration ability of the ship will descend along with the decrease depth of the water. Ship's maneuvering ability will be improved with the thruster.The research provides with the reference for the pilots and captains on safe control of the vessel maneuvering. It brings forward a new research field in safety assessment of vessel operation, and ship maneuvering simulator.