Simulation Of Ship Maneuvering Motion In Waves

Ship maneuverability is one of ship motion capabilities, which indicates the performance of a ship to maintain or change its velocity, direction and position by the control of helmsman. It influences the economics and securities of shipping. With the development of international shipping, there emerge more diversity of ships with larger sizes and higher speed. Busier-routes bring more accidents of sea transportation. So people think more of ship maneuverability.Traditionally, to the research of ship maneuvering, people usually focuses on the ship maneuverability in calm water. However, the sea that ship sails will never be calm, there will be waves and some times large waves in the sea, so to research ship maneuverability in waves have some signification both theoretically and practically. Now, there already exists a mature system of theoretical and experimental methods to investigate the ship maneuverability in calm water, and to the ship maneuverability in regular waves, some mathematical models have been developed and some research has been done. However, to the ship maneuverability in random waves, there have been few publications.In this paper, a six degrees of freedom mathematical model encompassing calm water maneuvering and traditional seakeeping theories is developed to simulate the ship maneuvering motion in both regular and random waves. The horizontal body axes system is used in this model. In order to complete the simulation of ship maneuvering motion in random waves, the Runge-Kutta method is used to get the solution of the equations of this mathematical model. The main content is introduced as follows.The advances in the research of ship motion and ship maneuvering were reviewed comprehensively at first.The interrelated theories of ship maneuverability were introduced, especially focusing on the mathematical model describing ship maneuvering motions in calm water. Then the MMG model was used to simulate the maneuvering motions of a container ship.The traditional seakeeping theories were introduced, focusing on the time domain equations and frequency domain equations of ship motion in waves and the relations between them. Added mass, damping coefficients and wave forces were calculated mathematically, and for the wave forces, experiments were carried out to validate the numerical results.A six degrees of freedom mathematical model encompassing calm water maneuvering and traditional seakeeping theories is developed to simulate the ship maneuvering motion in waves. This model was used to simulate the maneuvering motions of a container ship in waves .