Because the mooring facility is usually considered as a fixed type construction, the fendering system for mooring facility needs to support the total ship’s impact caused by berthing and mooring of ship. Basically, piles which compose dolphins or piers are deformed, and also absorb a part of the ship’s impact. In this paper, we have tried to reproduce the dynamic behavior of ship berthing phenomena by a numerical simulation method which considers a coupling effect of motions of the ship and the dolphins with fender deformation, and have investigated the accuracy through comparing with those of the observed test results of the actual VLCC’s berthing by Ueda.

In a traffic census, there are several problems to solve. It is time taking to identify the type of small ships which are not legally obligated to install the Automatic Identification System (AIS). It requires time to check the observed record. The observation accuracy becomes less as it tends to depend on the subjective judgement of the observation personnel, which is outstanding particularly in nighttime. Also, the experienced personnel in observation is short in number, which makes difficult to keep successors of the observation techniques.

In order to solve the problems, the authors review work saving and efficient ship type identification judgement by the ship images and the radar reflection intensity mainly with the observation of small ships. In our previous report, we reviewed the ship type identification using the radar reflection intensity distribution (B scope data) and Artificial Intelligence (AI) to solve the problems. In this study, while keeping the ship type identification by the ship images, we reviewed the ship detection and ship type identification using the object detection technique for the first time, and herein we report the outcome.

During the maintenance and construction of offshore structures, it is necessary to ensure calmness in terms of safety and workability in the relevant sea area. In this study, we statistically analyzed the observation data of GPS wave gauges in open seas from the Japanese wave information network (Nationwide Ocean Wave information network for Ports and HArborS: NOWPHAS), and clarified the occurrence of missing data and the number of consecutive days of calm conditions. Based on this, the number of calm conditions that last for three consecutive days or more, which is defined as the minimum required for construction, occurs only two to three times per month. For this reason, it became clear that the maintenance and construction of offshore structures are extremely difficult. Finally, the correlation analysis is conducted to know the relation among the occurrence of missing data, the number of consecutive days of calm conditions, and the statistical values of wave heights.

The Kanmon sea area is a marine traffic congested area and a rich fishing ground in Japanese coastal sea area. Authors have studied any analysis of actual marine traffic condition, fishing condition, conflict condition between fishing boats and vessels in this area. As a further study, authors have investigated opinions of 225 navigational watch keepers of the domestic vessel regarding reduction of conflict between fishing boats and domestic vessels in this area through a questionnaire. This paper has been analyzed opinions of these watch keepers and compared past outcomes of author’s study with opinions of these watch keepers. These analyses revealed any detailed actual conditions of this conflict, and any differences between conditions which these watch keepers are allowed and actual conditions of this conflict.

Statistical properties of winds and waves in smooth water areas established in Kyushu and Hokkaido are investigated by using numerical prediction data. These data are homogeneous in time and space, thereby, stochastic evaluation between areas is possible for data of 10 years. In this paper, the characteristics of winds and waves between the areas are investigated relatively. From the investigation, the joint probability density of height-period-direction of waves shows useful information on wave development and damping process which are affected by the geographical features.

This paper reports the results of a study on route prediction for fishing vessels with the aim of reducing collisions among vessels, including fishing vessels. The authors used LSTM (Long Short-Term Memory), a type of recurrent neural network, to construct a prediction model that learned past trajectory data from AIS data of fishing vessels operating in the Pacific Ocean, and then predicted the route of the fishing vessels.

The results of the fishing vessel route prediction showed that using SOG (Speed over the ground), COG (Course over the ground) and Heading as explanatory variables, in addition to latitude, longitude and time, gave better prediction results for highly nonlinear input trajectories. Future work is to improve the prediction accuracy by focusing on the differences in routes for different types of fishing vessels.

In this study, we analyzed AMeDAS wind data from five Japan Meteorological Agency’s stations and discussed the wind speed and gust factor for each wind direction. The gust factor was larger on land than on the sea, and the correlation between wind speed and gust factor tended to be higher on the sea. As a result of the investigation, there was a case with a maximum instantaneous wind speed of 16m/s and a gust factor of 2.86. This gust was conspicuously caused by the passage of a front with strong rainfall intensity. At Kobe and Kansai International Airport, it was found that the winds became stronger when the wind direction changed from SSE to SSW, and marine accidents had occurred due to this phenomenon. These findings can be used to make operational decisions and help prevent maritime accidents.

The working environment for seafarers has improved dramatically due to improvements in ship functions, various legal measures, and efforts and innovations by both labor and management to improve the workplace. However, life at sea for seafarers is fundamentally harsh, as they operate ships in a highly volatile environment and are unable to take adequate and continuous rest periods. They also live at work for long periods of time, a situation that is far more difficult than the working environment for land-based workers. As a result, the accident occurrence among seafarers has always exceeded that of accidents on land, and is about four times higher than that of land-based accidents. This study focuses on the mental health of seafarers, particularly the effects of fatigue and stress, and to extract and structure risk factors using multivariate analysis techniques to consolidate the knowledge necessary to maintain the health of seafarers' mental health.

Based on the results of the questionnaire survey, risk factors affecting the mental health of seafarers were extracted, and the results of correspondence analysis and text-mining analysis of free descriptions provided useful information for maintaining the mental health of seafarers.

Operators who engaged in vessel traffic services provide a variety of information to vessels in order to enhance the safety and efficiency of marine traffic. In this study, fixation time of the operator’s eye were analyzed using two eye tracking devices to investigate the real work of VTS operators, who are usually two-person teams at Shimizu Port Radio. The results of analysis with equipment and materials as area of interest in the operation room showed a tendency for the division of work to be determined by the arrangement of equipment. It was confirmed that the time spent looking at the display showing various relevant information of VTS was about half of the time spend on the job, compared with maritime observation and document reading. Also, the operators simultaneously preparing documentation while were communicating via VHF, suggesting that workspace was an important aspect. From the viewpoint of improving the operator's work environment, we also consider importance to design the monitor and equipment layout.

The possible missions of the autonomous navigation robot ship include collecting marine plastic waste in harbors or coral reef waters, mother ships for underwater equipment such as underwater robots, unmanned ocean observation platforms, maintenance of marine structures such as offshore wind power facilities, automatic feeding systems for smart aquaculture, etc. These cannot be said to have a large commercial economic scale at present, and it is necessary to develop unmanned technology that can be operated at low cost. In order to establish autonomous navigation performance technology, it is necessary to accumulate knowledge through actual sea trials. The authors have been developing a small catamaran-type USV(Unmanned Surface Vehicle) with the aim of constructing a system that allows repeated real-sea experiments relatively easily. In this paper, we report the results of actual sea experiments conducted to confirm the control performance of keeping a fixed point and of moving to a target point, and we discuss some issues that have been found through the experiments.

The floating tsunami protection wharf (FTPW) has been proposed as a tsunami protection measure for vessels moored at wharves. The FTPW is a useful floating pier that can prevent the breaking of mooring lines and the grounding at a wharf by the leading waves of a tsunami. However, placing the FTPW that occupies a large area of the port can be difficult, and negative effects on cargo works can result from motions of the FTPW where cargo handling equipment is located because of the waves. In this study, we have proposed the use of floating tsunami mooring bitts (FTMB) to address these FTPW problems. We performed tsunami simulations to verify the floating and disaster prevention performance of the FTMB using the 3-dimensional moving particle simulation (MPS) method. Our results show that the FTMB not only can prevent tsunami damage to moored vessels but also have the effect of disaster mitigation by delaying the tsunami inflow time to the wharf.