In this paper, the motion behaviors including hydrodynamic interaction effect between LNG-FPSO and Side-by-Side positioned LNG carrier in various heading angle waves are studied by using a linearized threedimensional potential theory. Numerical calculations have been carried out for twelve coupled linear motion responses and relative motions between two floating structures in waves using three-dimensional pulsating source distribution techniques. The numerical results give a good correlation with the well-known experimental and theoretical results. Based on the relative motion results in regular waves, we performed analysis for the relative motion at loading arm point in irregular waves using JONSWAP sea spectrum. The numerical results show the present tool can be used effectively to predict the motion responses of multiple offshore floating structures in waves.
Currently, many governments in the world have interest in LNG (Liquefied Natural Gas) as a clean energy, and are concerned with expanding the use of this type of gas. Many oil companies also have interest in the collection of LNG and development of the marginal field. The LNG-FPSO developments between oil majors and consulting companies have been discussed since the 1990s, but have never come to fruition. SHI(Samsung Heavy Industries, Co. Ltd.) has expressed much interest in it, and developed the concept design for the new LNGFPSO hull shape in which the reduction of roll motion and sloshing loads was focused(Ha and Kim, 2002). Offshore offloading operations take place in many locations throughout the world as oil or gas field moves deeper offshore area. In general, many offshore operations involve the use of two or more floating structures, which are positioned closely to transfer oil or gas during offloading operation. Consequently, it is expected that they affect each other's motion responses through hydrodynamic interaction between two floating bodies in waves.
