Simulation of ship maneuvering motion in random waves

In the 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 random waves.The horizontal body axes system is used in this model.All the hydrodynamic forces and coefficients for maneuveriog are calculated by empirical formulates;and those for seakeeping except the second order wave forces are calculated in the time domain,in which the first order wave forces are the convolution of the impulse response function and the memory effects can be got by the convolution of the time-delay function;and for the second order wave forces,only the constant components are considered.Then,the numerical simulations of the turning motion of a container ship are performed in calm water,regular waves and random waves,the affections of the waves to the turning motion of the ship are also discussed.The results show that the effect of the first order wave forces on the ship maneuvering motion is not obvious and the second order wave forces must be taken into account when researching ship maneuvering motion in waves.