Study On Key Techniques Of Navigation Safety Of VLC In Restricted Waters

With the building and running of large berth one after another in China,the volume of VLC(very large carrier)increased rapidly so as to expand the risk of navigation,Particularly,the entry into China ports of 400,000-DWT and 450,000-DWT bulk carrier brought new challenges.Key techniques of navigation for 40,000-DWT carrier in restricted waters such as UKC(under keel clearance),the control of tide-use and speed,and methods of berthing and unberthing and so on had not been solved well.Taking the navigation safety of entry into Dongjiakou Port of 400,000-DWT carrier as the object,the paper established a model of effect factors of navigation environment,put forwards the UKC application method,determined the control limits of tide-use and speed,studied adaptability of water depth and berthing techniques,set up the guarantee system of navigation safety,it therefore gave an solution to the corresponding key techniques said in the above paragraph.The contents detailed were as follows.a.The model of effect factors of navigation environment.It was analyzed through the application of man-ship-environment-management model in traffic schemes and combination with the characteristics in Dongjiakou Waters.b.Value and application of UKC and requirements of control of tide-use and speed.The value of UKC under different ways was obtained by the application of contrast method.And then,took conditions of tide-use into account fully,the application model of UKC was put forward,the relation among the UKC,the tidal level and maximum navigation draft was given.In addition,requirements of control of tide-use and speed were determined and the adaptability of water depth.c.Guarantee conditions of VLC into a port and key techniques of guarantee navigation safety.Taking comprehensively use of conclusions in UKC,control of tide-use and speed,combing with the model of effect factors of navigation environment,tug arrangement,recommended schemes of port entry,its prior conditions were put forward,the berthing techniques were analyzed and verified through the navigation simulation test.On the basis of above researches,a model of key techniques of guarantee of navigation safety was set up.d.Risk fuzzy evaluation of navigation safety.Methods of fuzzy comprehensive evaluation,analytic hierarchy process and xpert judgement were applied so as to evaluate the navigation risks according the model of effect factors of navigation environment.The fruits in the paper could enrich the theory of UKC and its application,perfect the theoretical basis of controls of tide-use and speed of VLC,improve the manoeuvring techniques,therefore,pushed forward the maximum use of water resource on the premise of safety,which was in favor of good and rapid port development.