Study On The Method To Determine Voyage Economical Speed Of Deepwater Environment Protection Vessel On EEDI

With the development of marine resources exploitation,there is a significant increase in the number of offshore platforms and deep-water environment protection vessel?DEPV?.As a kind of Multi-purpose Marine Working Boats,DEPV services at offshore oilfield,it is with combination functions of cruise,supply,oil recovery,firefighting,rescue and other functions in a vessel.As the international community is increasingly concerned about energy conservation of ships,the research on determining the economic speed of DEPV which can achieve energy conservation and emissions reduction is a feasible and effective measure.In this paper,the characteristics of DEPV are analyzed,in terms of the navigation area,the condition of DEPV's navigation area is so complex that the impact on the speed should take into account;in terms of working conditions,due to the diversity of functions,DEPV may have the characteristics of cargo ships,fire boats,tug boats and others which should deal with the classification;in terms of the profitable,as a multifunctional tramp vessel,it's hard to price DEPV's functions,and sailing time is usually limited,so that the method of determining DEPV's economic speed is different from traditional methods.What's more,in order to highlight the environmental characteristics of DEPV,according to the influence of greenhouse gases to the ship operating cost,the measures which are used to limit greenhouse gases emissions of ships are taken into consideration,and the environmental performance of DEPV is appraised by the formula of CO₂ emissions which is based on EEDI.Based on the existing methods of determining ships'economic speed,an economic speed model for DEPV is established with voyage total cost function of economic performance,CO2 emissions function of environmental performance and time penalty function of rapidity,then through K-means clustering algorithm and Gauss projection,the lane of DEPV is divided into several parts,and sailing characteristic curves is solved by CFD simulation technology and the functions relation between variables are shown by polynomial fit.Finally,after building multi-objective optimization algorithms and optimization rules,the calculation software for determining DEPV's economic speed is produced by programming,and an example is presented to verify the feasibility of the model.Through the research on economic speed of DEPV,a multi-objective model is established to guide DEPV's speed with economy,technicality and environment,through developing calculation software,it provides an effective way to realize intelligent navigation.