Recognition is to understand motion and present situation on other vessels correctly and regard them in danger. This study has verified substance of the recognition by analyzing speeches in bridge teams. Restricted visibility and existence of fishing boats request them to collect much and frequent information on targets. This action makes them understand the good recognition and realizes safe navigation. However; it has been also verified that the capacity of the frequency on the collection is once in 23 seconds or less. This paper theoretically shows that capacity suffocates safe navigation.
