Berth Operability Estimation Related to Ship Motion

The method of exposed berth operability estimation based on moored ship criteria for safe working and mooring is presented. The solution methodology consists of modelling a ship as a panel model used to calculate the hydrodynamic loads and responses from the potential theory. The mooring lines are modelled by ship-to-ground spring elements. The stiffness of those elements is accumulated in the global restoring matrix of the rigid body equations of motion. The obtained system of differential equations is solved by the frequency domain procedure taking explicitly into account the influence of shallow water. The effect of irregular waves is taken into account by an appropriate wave spectrum. The wave scatter diagram and wave direction statistics allow the estimation of the probability and parameters of most severe sea based on long-term statistics. Illustrative applications of the method are given for several ships moored on the outer side of a jetty. The irregular sea is described by the Tabain spectrum. The significant values of the ship ramp displacements and velocities are compared with specific criteria limits