Performance changes of an engineering ship with one mooring line failure

Abstract

This paper analyzed the performance changes of an engineering ship with mooring line failure. The nonlinear numerical model of the hull-mooring system was established through a fully coupled dynamic analysis program - ANSYS/AQWA. At a certain time, one of the four mooring lines was intentionally disconnected. The dynamic responses of the ship, the mooring line tension and the transient effects of the slow-drift motions with mooring line failure were investigated in detail under the environmental conditions. After a series of numerical simulations were conducted, the results showed that the accidental failure of one mooring line changes the watch circle of the ship and causes the tension redistribution of the damaged mooring system. In addition, the results also indicated that the current practice should consider the transient effects after the mooring line breaks because it may cause the transient overshoot of the slow-drift motion. Consequently, it is necessary to evaluate the safety condition of the ship with mooring line failure in advance. This study could give a profound understanding of the influence of mooring line failure and have reference value in the design of the mooring system.