Study On Vessel Maximum Velocity With Tugboat Assistance In Harbor

This thesis explores the vessel maximum velocity with tugboat assistance in harbor based on the ship maneuvering mathematical model.According to the MMG's separated modeling theory, an integrated mathematical model is established, which can be applied to ship maneuvering with tugboat assistance in harbor. The model has taken in account the following factors: hydrodynamic forces and moments acting on the hull, propeller and rudder of the vessel, and the hydrodynamic interaction among them; the characteristics of the maneuverability in shallow water and in low speed; the variable forces and moments acting on the tugboat. The paper also elaborates on the calculating method, the Runge-Kutta method and the Grads method. By integrating C++ with MATLAB through the programming process, the research simulates the trials on the ship maneuverability.The thesis presents a quantitative analysis of the maximum velocity with tugboat assistance at the fore part of vessel. Grounded on a comprehensive discussion of the effects of tonnage, loading condition, ratio of water depth to draft and tugboat power, the thesis puts forward the assessment curves as well as the regression formulae.The study has obtained the following conclusion: the increase of tonnage or the decrease of water depth will lead to an obvious decrease of the maximum velocity, while the increase of the tugboat power causes an unconspicuous increase of the maximum velocity.The research provides with the reference for the pilots and captains on safe control of the vessel maximum velocity with tugboat assistance. It brings forward a new research field in safety assessment of vessel operation, and a new idea to develop the ship-handling simulator.