In our previous study, investigations on property of ship motions was conducted through a numerical simulation and a field observation of ship motions and mooring loads. From the investigations, it was concluded that low-frequency motions such as sway, surge and yaw were induced significantly by resonant effects with the long-period wave, and resonant roll motion also occurred at the berth due to the swell component of the wave. It is important for the investigations on property of the ship motions to estimate the natural periods of each ship motion and damping effects precisely as possible. In this study, we have conducted a physical model test on free oscillations of the model ship for a large vessel moored along dolphin to obtain the property of the natural periods and the damping effects.

There are many cases when a fishing skipper dies by a collision between a fishing vessels and a merchant vessel. Act on Preventing Collision at Sea require vessels to keep a proper lookout at all times. However, as fishing vessels can't always employ an Officer of the Watch(OOW), bad lookouts are the cause of many collisions.

This paper examined cases when vessels didn't keep proper look out between fishing vessels and merchant vessels in the judgment of Japan marine accident inquiries. As a result of the examination, it was clear that there was “prejudice” in the stage before "risk of collision" in both vessels.

This paper pointed out the problems of “prejudice,” and also suggested to get measures for accidents according to prejudice.

In the marine traffic environment in the recent years, the state of displaying the marine traffic information on the radar screen has been improved due to the increasing use of AIS. This fact is certainly related to the improved safety of marine traffic. However, as still there are a large number of vessels operated without AIS, it is concerned that there is a potential risk due to the difference of the information volume between the vessels with AIS and those without AIS.

Under these circumstances, the authors set a goal to develop a method of risk assessment based on the ship traffic environment with the vessels of different information level. We tried to make a simple model regarding the features of the distance sailed to abeam based on the radar observation data. Using the same data, we picked up the data of the group in which two vessels sail head-on, and explained the features of the distance sailed ahead at every distance abeam within a certain area. In this study, we propose a new method of risk assessment by the true motion using the result obtained so far.

Wave disasters have been caused since long ago by swells which are called Yorimawarinami on the coast of Toyama Wan, and predicting the swells is important to prevent wave disasters. But it is difficult to predict the swells precisely by numerical wave prediction only, therefore we consider swell prediction system based on wave observation. It is investigated on the availability of swell observation by radar in coastal waters.

The results of the investigation are as follows:

(1)It is possible to catch wave crest lines of swells with significant wave period of 10 seconds or more and significant wave height of 1 meter or more, clearly by radar in coastal waters.

(2)It has become clear that a cause of phenomena of swell height increasing in a certain water area off the coast of Ebie is that the swells gather together as a result of refraction due to coastal topography.

(3)There is a possibility of observing swell's beat with long period more than several minutes by radar.

There are about 2,000 maritime experts in South Korea annually. but, high quality sailors avoid sailing on coastal ships. Korea is worried about the aging of coastal vessels and the increase in foreign sailors, as this points are. directly linked to shipping traffic problems that cannot be secured by the coastal sailors of good quality.

Therefore, this paper will discuss the current situation of the seafaring educational system in Korea. The seamen's policy in Korea, and the influence of seamen's policy. Despite the fact that about 2,000 seamen are cultivated each year, fewer people are trying to become seamen. In the case of a crew member of a coastal vessel, the tendency is even more severe. Concerning problems such as the policy for sailors and their service, this paper focused on problems that did not show at the surface level.

This paper will clarify the actual situation from an occupational prestige investigation about the intentionality to the seafaring occupation. This paper suggests that the security of the members of the Korean coastal vessel after investigating the actual situation from an occupation prestige investigation.

In the previous paper, a checklist for analyzing capsizing accidents in waves was proposed by scrutinizing investigation reports of capsizing accidents published by Japan Transport Safety Board (JTSB). In this paper, the checklist was applied to written adjudications of capsizing accidents published by Japan Marine Accident Tribunal (JMAT) to include any factor which was not found in the investigation reports of JTSB.

Then, the checklist was modified so that it could be applied to sinking and listing accidents. By applying the modified checklist to sinking and listing accidents in the investigation reports and the written adjudications, factors which need countermeasures against sinking and listing accidents were clarified. A way of thinking about countermeasures of accidents in waves was organized from the analysis results of the previous paper and this paper.

The ratio of collision is high in a marine accident. The collisions occur frequently in a congested sea area and they tend to occur for a similar place and a cause repeatedly. Therefore, it becomes the prevention of recurrence of the accident when ship operators know the outbreak situation of the collision of the navigation area before the operation. In previous study, it was revealed that the area with many accidents changed by time. However, the time influence could be evaluated by a comparison of cross-section maps with arbitrary time intervals.

In this study, the collision occurrence state was represented in a three-dimensional space composed of two-dimensional geographical plane and one-time dimension. To understand spatio-temporal pattern of collision occurrence state, I expanded kernel density estimation in the three dimensions from the two dimensions. Because the collision occurrence probability density in any coordinate was found, it is possible to find the density on the planned route. I changed speed as well as the departure time from a port, and a comparison was enabled with the risk of the route.

Northern Kyusyu was hit by the record heavy rain between July 5th and 6th, 2017. The fishing industry has been negatively impacted by a large amount of driftwood flowing into the Sea of Ariake and Suonada. It was reported that fishing vessels are damaged by contact with the driftwood. Therefore, it is imperative to characterize the danger that driftwood presents to fishermen to ensure their occupational safety. In this study, we aim to calculate the impact force when a fishing boat collides with driftwood using the equation of motion and considering the contact stiffness. Moreover, we created the poster to convey the obtained information and promote safety and displayed it in the Usuki branch office of the Oita prefecture fisheries cooperative.

In the past, the maritime industry has approached the matter of maritime safety from a predominantly technical lens. The reliance on technical hardware to maintain marine safety is evidenced through the many innovations to and requirements concerning ship design and equipment. However, despite these many preventative technical innovations, marine accidents have continued to occur.

However, in the fields of aviation, medicine, and nuclear energy, which all have complicated operational systems, the study of non-technical skills is included for the purpose of maintaining safety.

We suggest that the risk of marine accidents can be decreased through the appropriate implementation of non-technical skills in the maritime industry. We apply the concepts of non-technical skills to a human factor analysis of ship operators (which includes pilots). In this paper, through the classification of ship operator behavior as elements of non-technical skills, we analyze these non-technical skills and discuss how the application of non-technical skills can be used to prevent marine accidents.

After the building of the ship taking over the “Kaiwo Maru I” was planned, in Shinminato City (at the time), devoted movement inviting her had been developed since around 1980. In 1990 she was moored at Fushiki-Toyama port temporarily, and “Kaiwomaru Park” was built two years later. In 1994, permanent preservation of her (at Fushiki-Toyama port) was decided. Afterward, events such as full-sail exhibition or maritime educational program have been held. Through these efforts, the “Kaiwo Maru I” increases visitor's knowledge and interest in ocean and ships. She also has contributed to maritime education for the younger generation. We first specify the detail of inviting her that many people made efforts and achievements after her retirement. Then, in order to leave the “Kaiwo Maru I” eternally for the next generation, we propose the significance of her existence and how she can contribute to society that are able to win people's understanding in both hardware based and software based (tangible and intangible) elements.

In ship-handling, when given navigational situations become difficult to deal with, a bridge team is organized in order to share necessary tasks among team members for achieving sustainable safe navigation. However, bridge teams do not always realize such an intention. That is why Bridge Team Management (hereinafter called "BTM") is essential to maintain cohesive and consistent teamwork.

With this in mind, the authors focus on functional communication among bridge team members which is an important factor for executing BTM. In this paper, the authors analyze the contents of information exchanged among team members during collision avoiding maneuvers, and define necessary functions for achieving safe navigation by utilizing tree structures. The proposed tree structures reveal necessary functions by utilizing combinations of information for avoiding collisions with oncoming vessels. Based on these tree structures, the achievement degree of communication in a bridge team is evaluated quantitatively. It is hoped that this new area of research will contribute to more effective bridge teamwork, reducing the risk of collision.

In collision avoiding maneuvers, the standard navigational procedures are stipulated by laws such as the International Regulation for Preventing Collisions at Sea. Based on such laws, well-experienced seafarers combine their normative approach they have developed through their experience in order to determine a corresponding course of action. Therefore, analyzing their procedures for avoiding collisions would provide us with valuable insights into judging the risk of collision with oncoming vessels. In addition, when reviewing such procedures, a rational basis for judging the risk of collision can be examined. With this in mind, the authors study well-experienced seafarers’ lookout procedures for collision avoiding situations methodically set up by a ship-handling simulator. Especially in this study, eye-tracking technology is additionally utilized for detailed analyzing of seafarers’ data gathering by their lookout procedures. Utilizing this technology enables concrete information for each encountering situation seafarers acquire by their visual inspections, radar observation and scanning with binoculars, to be revealed. The authors suggest such procedures would be beneficial when judging the risk of collision and would serve as a valuable perspective in education and training, teamwork.

In this research, we aim to detect ships sailing around our ship from river navigation images using Faster R-CNN and predict their course. We changed the parameters of Faster R-CNN and compared detection rates of ships. We detected navigating ships as obstacles using the best discriminator and river navigation images for evaluation. We predicted the course of the detected navigating ships. The results are summarized as follows:

(1)We created data set of eleven categories that can be used for machine learning from learning river environment images.

(2)We detected sailing ships using Faster R-CNN. We examined the detection rate by changing resizer image, anchor size and number of times of learning which are parameters of Faster R-CNN.

(3)We carried out course prediction from the detected navigating ship's position information. We evaluated the accuracy of predicted course.

Container terminal acts as an important intermodal node that connects cargo sea and land transportation mode. It is an important infrastructure supporting Japan's socioeconomic activities. Maritime container logistics faces many challenges environmental issues such as reduction of CO2 at ports and operational costs for international competition. A solution of introducing electric RTG system is effective to suppress greenhouse gas emission, but there are some problems such as the increase in total amount of electrical consumption and a peak of electric consumption especially during summer. In this study, we construct a detail simulation model of seaside operation of container terminal with consideration of restriction of electric usage and examine the influence of electric RTG deployment system to suppress the power peak in Hakata Island City Container Terminal.

In a pivot-turn maneuver, initially, two tugboats are located ahead of and near to an LNG carrier. When the tugboats push in the directions of 3 and 9 o'clock in calm seas, the LNG carrier can be pivoted to the right. However, under the effect of wind and the associated drift of LNG, it is not feasible to pivot an LNG carrier in narrow port areas as it would pose a risk to various nearby structures such as the quay. Because the superstructure of an LNG carrier is larger than that of the other ships, only the wind forces in port areas are considered to affect the maneuvering conditions herein, and the tidal current in the port area can be neglected. It is generally difficult to detect the point at which an LNG drifts from the center during a pivot turn based only on the visual evaluation of a crew; moreover, even if crews detect the present position due to drifting using various navigation equipment, such as GPS, ECDIS, the drifting cannot be prevented. However, no studies have yet been conducted regarding the appropriate combination of thrust vectors from two tugboats to reduce drifting. Hence, we propose a novel method to minimize drifting and validate this approach using a maneuver simulator.