EVALUATION FOR BALLAST TANK DRAINAGE BY HYDRAULICS EXPERIMENT

The quality of the ballast water drainage system during the cargo handling process of ships is an important issue for those involved in marine transportation such as cargo owners and shipping companies as it is significantly related to their revenue shipping. An excess charge is incurred if moored beyond the scheduled time due to the loading time, and the deadweight tonnage superfluity residual water reduces the deadweight tonnage. To minimize the loss of their transportation, this paper addressed two problems: shortening the ballast drainage time and minimizing the amount of residual water in the ballast tank. The objective of this study was to construct an optimal ballast drainage system to solve these problems. In this paper, hydraulic experiments modelling the drainage of the ballast tank were conducted to evaluate the drainage system's design policy and reveal the optimum design condition of a ballast tank.