Original articles
Stability assessment for intact ships in the light of model experiments
NAOYA UMEDA1, AKIHIKO MATSUDA2, MASAMI HAMAMOTO1, and SHIRO SUZUKI2
1 Department of Naval Architecture and Ocean Engineering, Graduate school of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
2 National Research Institute of Fisheries Engineering, Ibaraki, Japan
Abstract: A systematic method for assessing intact ship stability with a free-running model in a seakeeping and maneuvering basin is proposed in this paper. Model experiments were carried out in extremely steep regular waves for a model drifting, running in head seas, and quartering seas. This method was applied to two purse seiners, and efficiently identified thresholds in metacentric heights for capsizing of these ships. These capsizing thresholds are compared with requirements of the IMO Code on Intact Stability. This series of model experiments also confirms that capsizing at the threshold occurs only in quartering seas, and shows that capsizing is caused by broaching, loss of stability on a wave crest, or bow diving.
