Mooring analysis of an offshore berthed ship

This paper presents the results of mooring analysis considering both current and wind, for an offshore berth. A nonlinear analysis program for offshore berthed ship using iterative procedure has been developed. The mooring line stiffness and fender stiffness are transformed to the mass center of ship using appropriate transformation matrix and added to the hydrostatic stiffness of the ship. The exciting force due to wind and current is calculated considering the exposed windage area and immersed underwater area of the ship respectively. The elastic modulus of the mooring line and the fender stiffness are updated based on the forces in the mooring line and fender. If the mooring line is slack the elastic modulus is assumed to be zero. The study has been carried out for three ship sizes for a port proposed to be located in the State of Gujarat bounded by Gulf of Kutch and Gulf of Khambat. These two gulfs are ideal locations for offshore berth since they offer good shelter from waves.