Motions and safety of a floating liquefied natural gas and shuttle tanker during side-by-side offloading operations

Abstract

In recent years, the use of natural gas has remarkably increased due to growth in energy demands and concerns about the environment. Generally, pipelines are used for liquefied natural gas transportation; however, there are technical problems and cost increases in constructing liquefied natural gas pipelines in the deep sea. For this reason, floating liquefied natural gas system has attracted the attention of the industries, governments and academia. One of the major issues to be overcome in realisation of floating liquefied natural gas is the motion prediction of close-proximity floating bodies including the gap resonance between the two bodies. In this article, three steps were carried out in order to understand the ship motions and the gap resonance and their effects to the side-by-side offloading operations. First, the two-dimensional gap resonance between the two bodies was investigated using a viscous flow numerical method. Second, the three-dimensional gap resonance and the floating body motions were studied using a potential flow method and validated by the experimental model test. Finally, the limits of environmental conditions for the side-by-side offloading operations were examined by the results of numerical calculation.