Stabilization Of Unstable Fpso-Shuttle Tanker Motions

In this paper, a study is made on the dynamic stability of a FPSO-shuttle tanker system in terms of environmental conditions and mooring parameters. From the stability analysis, it is found that the ratio between wind and current velocities and the bow-hawser tension are most important parameters. Meanwhile, the hawser length is not significant for tandem offloading system in contrast to single-point mooring system. Two simple methods are proposed in order to stabilize the unstable fishtailing motion of the shuttle tanker. One is to keep the bow-hawser tension within a certain limit and the other is to control the heading of the shuttle tanker to be in head sea. Numerical examples demonstrate that the methods can effectively constrain the fishtailing motion.