The authors' previous study demonstrated that vessels which had an extremely short horizontal distance between two masthead lights, even in crossing situations, judged their own “Head-on situation” course by observing other vessels at night. In light of the conclusions from the previous research, this paper focuses on an analysis of a questionnaire survey for pilots, ocean-going officers, domestic officers, small boat operators and fishing boat operators. The contents of the questionnaire survey investigate ① “What length of the horizontal distance between two masthead lights are required for reducing the chances of misreading another vessel’s course?” ② “Do you know how to observe an extremely short horizontal distance between two masthead lights of another vessel?” ③ considered feasible measures. The results suggest that ① as the horizontal distance between two masthead lights widens, the number of people who judged another vessel’s course nearly 90 degrees angle of a “Crossing situation” increased; ② many people did not know how to correctly observe the vessel as it has an extremely short horizontal distance between two masthead lights at night, ③ it is important to introduce “how to see vessels with extremely short horizontal distance between two masthead lights (e.g. the Japan Maritime Self-Defense Force ship, the Japan Coast Guard vessel, the marine research vessel and the heavylift vessel) at night” to mariners in Japan and/or abroad. After a background review of this issue, this paper will analyze the data from the questionnaire results, and finally discuss conclusions and offer some suggestions for measures to correct any problems, as well as directions for future research.
Our study finally aims for the actualization that salivary NO3- can evaluate the mental workload of people in maritime society; navigators (captains), helmsmen, sea pilots, port-coordinators, and so on. The evaluation of salivary NO3- is currently not common as a physiological index, but it is reliable method for numerically expressing mental workload at any given time. People in maritime society sustain heavy mental workload on duty because they engage in duties around the clock. The analysis of salivary NO3- enables people in maritime society to recognize specific points in time where they themselves feel mental workload, and subsequently investigate methods to relieve stress caused by this workload. This paper will focus on port-coordinators as candidates in maritime society who deal with heavy mental workloads. Port-coordinators engage in keeping the safe of specific harbor/port around the clock in turns. This paper utilizes the evaluation list of port-coordinators’ duties in our study for the first time. This paper finally aims to revise and complete the evaluation list for port-coordinators themselves to locate, accumulate, and classify the navigational risky situations in the harbor/port, and finally to recognize and avoid the most risky situations. By doing so, this paper clarifies and accumulates specific points where port-coordinators feel mental workload from the analysis of salivary NO3-, and tries to classify those points into the evaluation list at the first onset. However, most items in the evaluation list did not correspond to the port-coordinators’ much mental workload. We need to consider and revise items in the evaluation list so that the list can be useful for port-coordinators’ duties and our study.
Navigational equipment is used to render accurate numerical data to Officers on Watch (OOW) so that they can maneuver well and navigate vessels safely. However, from the aspect of OOW, sometimes the large amounts of information and data generated by navigational equipment can be difficult to understand. COLREGS aren't always as useful as they need to be; they are collision avoidance rules that lack technical advice, which can occasionally cause problems for OOW during navigation. For example, COLREGS Rule 19 is generally defined as “Conduct of vessels in restricted visibility”. However, COLREGS do not provide any numerical standard for restricted visibility conditions that are necessary for the OOW, such as the specified values or numbers for vessel maneuvering. A brief summary of missing information from the COLREGS is as follows: ① Vessel size creates different time lags of reaction between ships or vessels after a “risk of collision” has been identified, ② The confusion of applying Rule 18 or Rule 19, ③ The failure to clarify current visibility as good or poor; and ④ Over-reliance on the information and data generated by navigational equipment. These four interconnected factors contribute to collision accidents under restricted visibility conditions. After an introduction to the legal background in this paper, the authors will further analyze the data collection from real collision cases, and finally conclude with some proposals to solve the problems outlined, as well as the directions for future research.
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