In order to find out optimum seed production date according to different defoliation and flooding period of Italian ryegrass, this studies with Tetrone were canied out on the experimental field of Honam Crop Experiment Station from 1986 to 1988. Treatment

In this paper, a program for the calculation of GZ curve for a ship in waves is developed and GZ curves for a ferry in the still water and in waves are calculated. And the added mass, damping, restoring forces and wave exciting forces are calculated by using the strip theory given by Salvesen, Tuck, Faltinsen. Capsizing simulations are perfoned in consideration if the nonlinear restoring forces of the ship in waves by using the Runge-Kutta 4-th method.