Fishing vessel accidents pose a challenge for both Japan and Vietnam. However, the differences in fishing vessel regulations between these two countries and the International Maritime Organization can be a barrier to improving their safety requirements. This study focuses on comparing the safety of Japanese and Vietnamese purse seiners in operation. A general comparison of principal parameters of Japanese and Vietnamese purse seiners is provided, followed by a comparison of the stability regulations for fishing vessels in Vietnam and Japan to determine any differences in safety requirements. Experimental investigations were then conducted to evaluate the seakeeping performance of Japanese purse seiners 199GT, 135GT, and Vietnamese MC11, including an analysis of their intact stability under the influence of fishing gear load and back rowing force.
The results show that the 135GT has less stability compared to the 199GT and the Vietnamese MC11, while the MC11 does not meet operability criteria even in average weather conditions. Additionally, differences in fishing methods between Japanese and Vietnamese purse seiners impact the vessel's heel angle and roll amplitude.
In Japan Marine Accident Inquiries, the phrase “innocuous passing” is used as a fixed phrase. However, among the accidents that were judged to be “innocuous passing” by Japan marine accident inquiries, some were found to be “innocuous passing” in proximity to larger vessels. As development and demonstration tests of Maritime Autonomous Surface Ships (MASS) proceed, there is concern that the emergence of autonomous vessels that operate on numerical algorithms may be affected if there are ambiguities, such as “innocuous passing,”, that are not specified in COLREGs. The survey on the distance at which a Japan Marine Accident Tribunal judges a case to be “innocuous passing” shows a trend in wide water areas. In addition, comparison with overseas judgments also clarified the difference between “safe passing distance” and “innocuous passing”. In the future, we believe that active discussions need to take place to provide general guidelines regarding concepts not mentioned in COLREGs, such as “innocuous passing”.
Remote ship operation has received substantial attention as a future approach for operating autonomous ships. To control ships from remote locations, remote ship operators must adequately comprehend the states of their own ships and their environment. However, remote ship operations are not well understood; for example, it remains unclear how remote ship operators determine the present states of their ships and what information is crucial for controlling ships from remote locations in emergency situations. To investigate how to handle emergencies and identify important information and functional requirements in remote ship operation, this study proposes a method for analyzing situation awareness, which is often defined as a state of knowledge achieved by remote ship operators. This method was developed through the study of simulation-based experiments using a remote maneuvering simulator. This study analyzed the process by which remote ship operators achieve situation awareness during the emergency breakdown of a remote system using the Situation Awareness Global Assessment Technique (SAGAT) (modified for this experiment). Specifically, the process was determined by analyzing the participants’ behaviors and eye gazes and conducting interviews with them. The results show that the interviewees’ responses were consistent with their behaviors and eye gazes.
Various studies have proposed different approaches for the automatic berthing system of ships. However, these studies have not achieved a well-balanced trade-off relationship between the accuracy and real-time performance in berthing control. Thus, in this paper, the author proposes a mission function control algorithm based on Lyapunov’s stability theory in aerospace engineering to overcome the berthing problem caused by the nonlinearity of ship manoeuvring motion. The berthing problem is divided into two phases: heading control and surge speed control. This division simplifies the motion and makes it more comprehensible to humans by copying the real manoeuvring action made by humans. The control law derived from the mission function control algorithm includes nonlinear feedback terms since the equation of surge motion is nonlinear. Numerical results show the effectiveness of the mission function control algorithm in addressing the berthing problem.
Current stern lights can be used during night lookout to gauge the presence of an approaching vessel, but since the light emission range of the stern light is wide at 67.5° on each side, it is difficult to estimate the direction of travel of vessels with these types of stern lights. This study aims to investigate more effective ways to determine if a vessel is approaching, and utilized a questionnaire survey to see if the introduction and expansion of side passage lights, which are currently used on Ultra Large Container Vessels (ULCVs), would solve the problem of the current stern lights. Analysis of the survey results discovered that these side passage lights contribute to a more accurate estimation of the approximate heading in nighttime overtaking conditions, although the accuracy is lower than that in the daytime. Furthermore, based on the results of the questionnaire, if side passage lights are widely adapted, it is unlikely that confusion will arise in the future, even if side passage lights are widely used by other vessels besides container vessels.