A Wave Basin Model Test Study for a Jackup Moored on the Dock

Liu, Lei (Shanghai Jiao Tong University) | Yuan, Hongtao (Shanghai Waigaoqiao Shipbuilding Co., Ltd.) | Yang, Jianmin (Shanghai Jiao Tong University) | Tian, Xinliang (Shanghai Jiao Tong University) | Li, Chunhui (Shanghai Waigaoqiao Shipbuilding Co., Ltd.) | Lu, Haining (Shanghai Jiao Tong University)


Offshore platforms under construction are normally moored on the dock during the outfitting stage. The safety of the platforms must be guaranteed during the whole stage of outfitting which may last for several months. This paper presents a wave basin model test study of a jackup moored on the dock in Shanghai Waigaoqiao shipyard in China. In the model test, the jackup and the sea states were scaled based on the Froude similarity law. The dynami c responses of the system, including the six degrees of freedom (6DOF) moti ons of the jackup and the barge, tensions on the mooring lines and the collision forces on the fenders, were measured in various sea states. Meanwhile, the current-and-wind-only sea states were simula ted and the dynamic responses were measured for comparison with those in the wave conditions. The mooring line tensions were found to excee d the strength of the lines in offshore wind conditions. And this phenomenon may be attributed to the decrease of the jackup's yaw m otion stiffness. In addition, several suggestions are proposed for optimizing the mooring system performance.