Abstract: “Most offshore structures in the South China Sea (SCS) region are designed according to the American Petroleum Institute (API) standards which are based on harsher sea conditions. As the SCS sea-state conditions are calmer compared to those of the Gulf of Mexico and the North Sea, the use of API standards will overdesign the structures. Wind speed, wave height and current speed are among the metocean conditions that are considered in the design of offshore structures. Current practices treat the three types of metocean conditions independently of one another. This paper will employ extreme value analysis (EVA) and joint probability (JP) method to analyze measured metocean data and to determine the associated wind speed and current speed given the 100-year extreme wave height. The results show that the design loads can be reduced by 30% for design of offshore structures in the SCS region.”

Keywords: Metocean, Extreme Values, Joint Probability, Mean Return Period.