Study On Mooring Layouts Of Crude Oil Transfer Operation At Sea

With the scale development of ship,more and more ports’ depth conditions can’t meet the requirement of those ships,especially some oil tankers,which have restricted access to domestic ports.In order to make the crude oil transport operation safer and more efficient,and increase the comprehensive competitiveness of our domestic ports,many port administrations carry out the ship to ship oil transfer operation at sea.The mooring layout is extremely important to guarantee the safety of those oil transfer operation,The Oil Companies International Marine Forum,which is a authoritative institution of ship to ship oil transfer field,merely recommends a minimum mooring layout standard.In Chinese most ports,the mooring layout’s breakage accidents occurred in the oil transfer operation.Therefore,it’s of great significance to study the layouts of mooring cable in ship to ship oil transfer operation.The ship oil transfer operation at anchorage will eventually stabilize in the wind,current and wave directions.At this time,the dual-ship system reaches the equilibrium state of external force,and the force balance between the larger ship and smaller one reach internal force balance by mooring cables and fenders.However,for a particular mooring layout,the force of every mooring line depends on the weather condition,beyond that,mooring layouts should also consider the number of lines,fasten points and other relevant factors.Based on the minimum mooring layout from OCIMF recommended and consideration of ship to ship oil transfer operation characteristics,this paper design different mooring layout schemes which include different fasten position,line number,and the setting of breast line.Then,the data of different angles between current and wind,wave were imported into the professional mooring calculation software,OPTIMOOR,the data of cable tension and relative motion of two ships were statistically analyzed by using variance and range analysis method.Next,the optimization of the mooring layouts was given to balance the cable tension and control the relative motion amplitude of two ships.Finally,the Transas full-task navigation simulator was used and the result shows that the proposed mooring layouts can batter ensure the safety of the oil transfer operation,which can provide some reference for the subsequent research on the ship to ship transfer operation.