Coupled Analysis of Hydrodynamic Responses of a Small Semi-Submersible Platform and a Large Floating Body

Abstract

This paper focuses on the hydrodynamic interaction between the large floating body and a small transfer platform in a jettyless floating transfer system. A high-order boundary-element method combined with a direct time-domain-solution method to calculate and analyze the hydrodynamic response of the small platform while berthed with the fixed large floating body and freely floating large body under wave action was applied and compared with the hydrodynamic response of a single small transfer platform. It was found that when the large floating body and the small transfer platform were both located on the leeward side, they had little mutual influence, and the hydrodynamic response agreed well with that of the single small transfer platform and the single large floating body. While the small platform was located on the leeward side of the large floating body, it significantly affected the hydrodynamic response of the platform, resulting in a significant reduction in horizontal motion and pitch motion, meaning that the shielding effect was significant. Within a certain range of wave periods, the heave-motion amplitudes can be significantly reduced, but beyond that range, they increase. Therefore, it is important to carefully consider the relative motions of LNG transport ships and small platforms when connecting them via aerial jumper pipes in jettyless floating transfer systems.