Abstract
In this study, a practical estimation method for wear and breakage of mooring chain is investigated. In the method, mooring tension and sliding angle between mooring links are estimated from measured buoy’s motion. At the towing tank of Osaka Metropolitan University, by using motion of a small scale model of buoy with single point slack moored for 75m sea depth, its mooring tension and its motion of the mooring chain are measured in irregular waves. From the results, it is found that the mooring tension at the mooring point is correlated with the vertical acceleration on the buoy regardless of significant wave height and period. Furthermore, it is also found that the sliding velocity at the mooring point is proportion to the pitching angular velocity of the buoy. These results indicate that the wear condition and the breakage possibility at mooring point can be estimated by measuring buoy’s motion. In addition, the feasibility of the wear and breakage possibility estimation for whole mooring chain by using an numerical simulation assimilated to the measured data is investigated.
