Analysis of Vertical Motions of Bonga FPSO in Harsh Environmental Condition

Abstract

The analysis of the uncoupled vertical motions of the Bonga FPSO is performed for unrestricted service. The study made use of Airy’s wave model and the strip theory, to determine the excitation forces and moments, hydrodynamic coefficients, and the RAOs. Spectral analysis was done on the basis of the above results with the Pierson-Moskowitz wave energy density spectrum using the 100-year return period storm data of the North Sea to predict the vessel responses in a realistic sea, as well as forecast the number of green water and slamming at the bow per hour. Furthermore, the (HaPMotA) computer programme written in MATLAB on the basis of the above theories was used for the analyses. As a result, the RAO diagrams, the response spectrum, force and moment diagrams, the responses for the modes of motion investigated, and the operability of the vessel in harsh environment were obtained. The result indicates that the freeboard needs to be increased to mitigate the effects of green water in the harsh environments