Experimental Study On Influencing Factors Of Mooring Line Forces For Large Ships

Based on the physical model experiment and large numbers of actual project experiment data, this paper studies various type ship different dock arrangement. Several effects exert an influence on ship mooring line forces, and discuss the relationship between zero dimension mooring line forces and zero dimension rolling period. The result indicates:There is no obvious difference to mooring line forces under different ship content. The mooring line forces are the result of interaction of ship motion and content. If the outside dynamic condition is certain, the mooring forces will increase with the increase of tonnage of ship when tonnage of ship is smaller. The ship content with maximum forces lies, the maximum integrative effect to velocity and inertia power (150-300 thousand ton), but the ship content may not the max. In the range of experiment, the mooring line forces to a ship are not larger than a 300 thousand ton when the ship content reaches 450 thousand. The mooring line forces distributing coefficient of various positions in a ship is connected with the comparative length λ_f to a certain location. The λ_f is smaller and the corresponding coefficient is bigger. The overall mooring line forces in the nonlinear arrangement is more reasonable than in the linear.The velocity of flow in the construction area is more than 1.5m/s. The short length of berth is unfavorable, whereas, reducing the length of berth can be considered.In the range of experiment, the mooring line forces in head rope and stern fast are comparatively big while the angle of incidence is zero. The transverse and inverse line is stronger when the incidence is ±22.5° and its value is 10-20 percent larger than of zero angle of incidence.Wave period greatly influence mooring line forces and it increase with wave period.The mooring line forces increase with velocity of current. The mooring lines forces of ship is complicated when the current is from the front of dock, but its increase with current velocity when from the back of dock.The mooring lines forces of average wave height has close relation with transverse rolling period ,it varies with ship load, within experiment ,It has good linear relation between zero dimension mooring lines forces and zero dimension transverse rolling period.