This paper presents a computational fluid dynamics (CFD) analysis method to evaluate the behavior of a ship in regular waves, assuming that the floating load is a pendulum. Evaluating the behavior of a ship in waves is very important from the point of view of safety and availability; in the CFD analysis, the overset grid method, which superimposes multiple meshes, is used to reproduce the motion of the ship. Periodic external forces are applied to the jib points to account for the effects of suspended load motion. The coupled motions of a hull and a lifting barge were calculated using the MBD (Multibody Dynamics) calculation method. The objective of this study is to develop a coupled motion simulation method that integrates an MBD solver and a CFD solver. Hydraulic experiments were also conducted to verify the accuracy of the analysis and to develop a two-way weak coupled analysis method to solve the time evolution of the hull and lifting motion in a wave field.