The Containerships Sailing Speed Optimization Considering Wind And Waves

Facing container transportation makert going warm again after a cold spell and increasing of eviromental consciousness,how to promote revenue with lower pollution emission is a key problem for container shipping companies.Sailing speed as a dominant factor has influence on variable cost and operating efficiency.It means that appropriate sailing speed is helpful for solving the proposed key problem.Hence,sailing speed optimization research is beneficial to control bunker consumption cost,allocate resource efficiently and promote revenue.A large number of related literatures are reviewed and summarized in terms of sailing speed optimization in this paper.We find that most studies have lost touch with reality.They don’t take sea conditions such as wind and waves into consideration.The main work about the proposed problems is as follows:(1)To quantify the effect of wind and waves on containerships,the power model based on energy conservation is proposed to estimate speed reduction.It can quantify the speed reduction caused by wind and waves.The numerical example results compared with fitting model reveal that the proposed power model is more practical,which is helpful to optimize sailing speed in wind and waves.(2)We propose sailing speed optmizaiton model to minimize operating cost considering speed reduction caused by wind and waves for containerships sailing along rhumb lines.How to determine appropriate sailing speed considering wind and waves is studied.As the propsed model is mixed-integar nonlinear programming,the dicrete method is employed to transform the poposed mixed-integer nonlinear programming into mixed-integer linear programming considering the requirement of sailing speed precision in practice,which not only guaranttes the preceison of solutions but also simplifies calculation.(3)The shipping route and sailing speed joint optimization model taking advantage of wind and waves having not an affect on the safety of ships is proposed for containerships sailing along great circle routes considering that great circle routes are characterized by wide saling area with less constrains and more available routes.Furthermore,to optimize sailing speed and shipping routes reasonably according to meteorologic information,an algorithm for obtaining meteorologic data based on network common data form along ship route is proposed for providing data support for appropriate optimizating shipping routes and sailing speed.(4)As joint optmizaiton model is NP Hard,an algorithm based on random perturbation modified differential evolution is designed for obtaining solutions.The proposed random perturbation modified differential evolution is used to generate alternative shipping routes and linear programming model is used to determine optimal sailing speed on the corresponding shipping route.The algorithm is executed to adjust sailing speed and alternative routes alternately by combining above two steps to obtain optimal sailing speed and corresponding route.The experimental results show that the proposed algorithm is effective and practicable.