When analyzing ship accidents, there may be doubts whether appropriate countermeasures had been taken to prevent known types of accidents. This study aimed to suggest possible solutions by investigating the status and issues associated with the implementation of countermeasures using importance–performance analysis (IPA), Borich’s needs assessment, and locus for focus models based on previously identified causes of the ship accidents. As a result, firstly, we confirmed that there is a need to enhance education and training on specific knowledge, understanding, and proficiency (KUP) regarding ship stability, emergency response, and type specific training. Secondly, we confirmed that there is a need for a system of monitoring a seafarer’s KUP even while onboard a vessel—that is, after completion of identified training. Additionally, it is necessary to improve the seafarers’ working environment, which is subject to regulations. Thirdly, difficulties in solving wrong practice parts of safety and efficiency, such as the costs associated with implementation of safety regulations, were identified as the main reasons for the causes of the “not amended yet” sector after accidents. Lastly, the tools that were employed in this analysis can be used to confirm the implementation status of the actions to be taken after a ship accident.