Research Of Anti-Overturning Ballast System For Large Semi-Submersible Crane Vessel

Faced with the increasing depletion of land resources and the gradual saturation of offshore continental shelf development,various countries have increased their efforts to develop deep-sea oil,the demand for semi-submersible crane vessel is also increasing day by day.However,the semi-submersible crane vessel will cause large vertical and horizontal overturning of the vessel in a short time during the lifting operation,which will seriously affect the safety of the vessel.Therefore,the anti-overturning ballast system based on the semi-submersible crane vessel plays an important role in the whole lifting operation process,and the research and design of the anti-overturning ballast system is particularly important.Taking the semi-submersible crane vessel OOS Gretha as an example,the pneumatic ballast discharging system and the gravity water injection system are successfully applied to the semi-submersible crane vessel,and the ballast water can be quickly adjusted during the lifting process by cooperating with the conventional ballast pump system.The design of the anti-overtuming ballast system which consists of conventional ballast pump,pneumatic ballast method and gravity water injection method is the first successful attempt on a large semi-submersible crane vessel in China.It realizes the lifting operation of 1,800 tons of goods by a single crane and 3,600 tons of goods jointly within 60 minutes,breaking the technological monopoly of European and American countries on large semi-submersible crane vessel.The research results of this paper have certain reference value and significance for the research and development of domestic semi-submersible crane vessel;(1)According to the relation between the lifting tonnage and the limiting angle in the lifting curve of the crane,the whole lifting process is safely split and simulated;(2)Using GHS analysis software to analyze the changes of ballast water in the ballast tanks in the front and back states and calculate the load adjustment time;(3)Interlock control of the sea valve,air vent valve and compressed air valve of the ballast tank to realize quick and automatic ballast water adjustment of the semi-submersible crane vessel according to the operating procedures.