Calculation of Environmental Load for a Large FPSO Undocking

Abstract Ship undocking is an essential process in the construction of large ship. Nowadays, the traditional empirical method is usually used to calculate the environmental load during large ship undocking of large ship and to determine the power and number of assistant tugboats in the world shipbuilding industry. Firstly, the OCIMF with traditional empirical formula mathematical model for solving the environmental load problem is established in this paper. According to the location of the dry dock and the meteorological and hydrological conditions while undocking, the environmental load of a large FPSO with different wind, wave, and current combination from 0°to 90°are is calculated by using the OCIMF with traditional empirical formula method, and then the influence of the wind, wave and current load on large FPSO are is analyzed. Secondly, the environmental load is calculated by using numerical simulation calculation method based on the same environment conditions. Through comparing the analysis results between the two calculation methods, the reliability of using the OCIMF method is testified reliable to large barge-type FPSO, and the maximum environmental load is determined. Lastly, as a result the undocking plan and the power and number of assistant tugboats are finally determined. The actual undocking project shows that the OCIMF with traditional empirical formula method is reliable for calculating the environmental load of a large barge-type FPSO.