This report is concerned with the response to the waves of a box-type platform with spuds (legs) and the forces acting on the spuds at touching bottom under wavy conditions.　
　The experiment carried out with a model vessel revealed that in the case of a box-type vessel of light draft, its damped natural period and response to the waves are approximated pretty well by the equation with a damping term of second degree.
　It showed that moment of inertia has no so strong influence on the damped natural period and that the dynamic ratio has not such a large value. Non linearity of the equation changes the dynamic ratio according to an in-put, resulting the value, even at the resonance point happpens to become less than 1.
　The way of touching bottom that causes no rotation takes larger value of axial compression acting on the spud, and the value has closer connection with the amount of pitching than with the kinetic energy. Bending force is driven from the calculation based on the total energies of drifting and pitching, assuming that both energies change into list of the vessel and deflection of spuds.