Experimental Research On Security Anchoring Conditions Of Bow-stern Mooring Of Single Fishing-boat In Harbor

The study of security anchoring conditions can ultimately come down to figuring out the anchor rope tensions and motion responses of boats berthing inside the harbor constructions as well as its surrounding waters. It is critical to conduct scientific research on security anchoring conditions of fishing-boat in harbor, and its dynamic response characteristics based on the external environment load. Above research will effectively promote processes including verifying the current standard values of permissible wave height in harbor, as well as designing and constructing the offshore engineering with fishing boat as a main ship type.This paper carried out a research on the mooring condition of bow-stern double mooring fishing-boat within port. A three-dimensional physical model was used for the experimental simulation, and the 275HP trawler was selected as a representative. The simulation results can be similarly concluded form both regular and irregular wave, and show that under load conditions with different combinations of wave, wind and flow, measured values including bow and stern anchor rope tensions and the particular motion component demonstrate increased along with wave height, varied according to the law of resonance changes when the wave period approaches the rolling period of boat, and increased along with the loading incident angle. Besides, with all the other conditions fixed, the anchor rope tensions of half-load fishing-boat appeared to be higher than those under unload condition, tensions with mooring water depth of h=4m were higher than those with h=6m. Both load condition and mooring water depth did not have much impact on the relatively particular motion component. Based on the simulation result, this paper demarcated the referential range of mooring admissible limitation of fishing-boat in harbor, and provided suggestion for securely anchoring under external environment load conditions.Based on the qualitative analysis, this paper respectively came up with an empirical formula by using dimensional analysis to estimate the bow and stern anchor rope tension and particular motion component under following load conditions:pure wave, combination of wave and wind, and wave together with flow. While the coefficients were determined based on the data results measured from physical model experiments using regression analysis. Above research aims at providing technical reference for the demarcation of mooring stability parameters as well as the practical design and furthermore application.