Research On Loading Decision-making Of Underway Replenishment At Sea

Replenishment ship is a unique type of ship which keeps other ships functioning well by providing fuel,food,fresh water and other supplements. As deeper water depth area is increasingly popular in the shipping industry,this kind of ship plays a crucial role in increasing the operation time and radius of other ships. Therefore, it is an interesting and challenging topic that what we can do to accomplish the whole replenishment process in a stable, safe, and high working efficient way. Based on this topic, several aspects are studied in detail including the calculation method of load change in the supplement process, the decision of cargo oil tank and the load adjustment of water ballast tank.Firstly, the stress characteristics are analyzed when load are changed at any position of replenishment ship, and the calculation method of floating state, stability and strength are summarized.Secondly, the distribution of ballast water is studied in the ideal and no-ideal state,respectively. Aiming to obtain the feasible solution, the adaptive step ergodic of permutation and combination is applied in terms of the cargo oil tank and the water ballast tank.Thirdly, one basis,which constraints of supply ship during operation,should be definite.The feasible strategy is regarded as the evaluation unit and constraints of supply ships are considered as evaluation standards, which contribute to establish multi-objective determinable matrix. Based on the application of TOPSIS, the algorithm alternatives are solved in the same trend and the dimensionless standard matrix is established. Then the relatively optimal replenishment solution can be obtained by checking the Euclidean distance between each scheme and ideal solution.Finally, the supplement determinable system is established based on the details carried out above and evaluation standards discussed above. The TOPSIS algorithm modified by permutation and combination is used to solve supply plan. In addition, artificial selection and modification module are combined with the existing example to analyze the results,and thus indicating the practicability of this system.