A comparative study on the fatigue life of mooring systems with different composition

In this paper, two different types of the mooring system for a FPSO are considered, which is supposed to be installed in Gulf of Mexico. One system consists of 16 mooring lines (four by four) and another one consists of 12 mooring lines (four by three). It is designed that the static system stiffness are almost the same. Then two mooring systems are analyzed from the viewpoint of the extreme load and the fatigue life. A time-domain computational code is used in order to determine the extreme tension, while the spectral method is implemented for estimating the fatigue life.In the extreme dynamic load case, two mooring systems have almost the same results. In consequence, the fatigue life differs only slightly.