Original
Numerical method for evaluating the righting performance of a lifejacket influenced by clothing
2022 年 7 巻 1 号 p. 11-20
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2022 年 7 巻 1 号 p. 11-20
In 2017, the Marine Accident Investigation Branch of the United Kingdom reported an accident involving a fishing vessel that resulted in the fatalities of three seafarers, who were found face-down in the water despite wearing lifejackets certified in accordance with international regulations. Following this marine accident, research has been conducted on the righting performance of lifejackets, and it has been noted that the righting performance is reduced when lifejackets are worn over clothing. According to the current international regulation, the righting performance of lifejackets is evaluated through righting tests using human test subjects wearing only swimming costumes. The influence of clothing is ignored in the righting tests of lifejackets to improve the reproducibility of the tests. To improve the righting performance of lifejackets, it is necessary to develop a method for evaluating the righting performance considering the influence of clothing.
In this study, a numerical method for evaluating the righting performance of lifejackets considering the effects of clothing is proposed. Righting tests using a model test subject and a human test subject were performed to validate the numerical evaluation method. The proposed method is based on the ship stability theory and calculates the longitudinal equilibrium posture and transverse GM value as indices of the righting performance. The effectiveness of this numerical evaluation method was confirmed by comparing the calculation results to those of righting tests using a model test subject.
