日本航海学会論文集 Vol. 135(2016)

Even now a casualty during ship berthing or cargo handling operation has being occurring. Furthermore it has been reported in ports exposed to high energy long-period wave conditions that an emergency unberthing operation was repeatedly conducted with mooring line and fender breakage due to the large ship motion. It is important for not only effective workability of cargo handling operation but also safe mooring of ship to measure and monitor the ship motions directly. In this study, we propose a conventional measurement method of moored ship motions by using GPS position data, which is observed at three positions on ship. A field observation has been conducted to confirm the accuracy of the method, and several considerations have been investigated.

There are a lot of accidents involving small ships in Japan. These accidents account for over 70% of all shiprelated accidents. In 2008, large ships such as tankers, cargo ships, etc., were required to install AIS (Automatic Identification System) by Japanese law, in order to reduce accidents. After installing AIS, these accidents have dropped by about 50%. AIS is very useful in preventing marine accidents. However, a large percentage of small ship in Japan doesn't have AIS installed. AIS is too expensive and a license is required to have one installed.
In this study, authors are developing a navigation support system which uses a smartphone. This system gets the user's position, and send it to a server. This server then receives AIS ship data from a AIS station. This information is shared to all clients. By testing at coastal areas, it is confirmed that system is operated normally. From a survey conducted after testing, crews think that this system is expected to be affordable and effective in reducing accidents.

It is known that there are periodic water level fluctuations off the coast of Toyama Wan. Investigation on the periodic water level fluctuations was carried out to prevent wave disasters by wave observations and wave generating experiment. Water levels were observed at three points of Toyama New Port, Iwasehama and Iida Wan. The water level fluctuations with the periods of about 10 minutes or more were investigated using the water level data observed at the three points and wave generating experiment data.
The results of this investigation are:
(1)The water level fluctuations with the periods from about 10 minutes to about 1 hour are proper oscillations driven by water level fluctuations due to moving low atmospheric pressure or earthquake, in horizontal shallow water off the coast.
(2)Proper oscillation with the period of about 36 minutes between the Toyama coast and the southern coast of apex of Noto peninsula, causes a beat phenomenon with the same period as the proper oscillation period to swells which invade Toyama Wan from north.
(3)There is greater tsunami risk on the coast of Iida Wan as compared with the Toyama coast.

This study addresses the container block sizing problem at container terminals with irregular configuration. New marine container terminals often have a rectangular configuration by making use of reclaimed land. However due to geographical reasons some terminals have an irregular configuration. At the irregular configuration terminal that Rubber Tyred Gantry crane (RTG) operated, the yard capacity for container stored depends on the aisle locations and number of aisles that yard trailers move. In this paper, we consider container block sizing problem as aisle arrangement problem at the arbitrary configuration, in order to maximize the storage capacity and minimize the standard deviation of travel distances by quay side location. From the computational results, we can find a part of solutions that proposed approach outperforms the existing one.

The horizontal distance between the two masthead lights or between the sternlight and the second masthead light abaft of the forward one are enlarged with the specialization and the increasing size of vessels. As an example, the navigation lights exhibited on TI-class supertanker (380 meter in length, the horizontal distance between the two masthead lights are approximately 300 meters) are taken up as a sample of a vessel and her navigation lights are displayed on the screen of a ship-handling simulator in a moonless night situation. Seafarers watching her masthead lights and her sidelights from a small craft in the simulator have mistaken one large tanker as two small ships and have also misunderstood her heading direction. As a similar problem, navigation lights of very large container vessels constructed in recent years and of towing vessels are discussed and necessities of drastic measures on navigation lights including a revision of Colregs are pointed out.

Developments of autonomous ships are progressed in the world and algorithms for automatic collision avoidance or its decision support are widely required. Following factors are essential for the algorithm such as, selection of a target ship to avoid collision risks; determination of a start time of collision avoidance manoeuvre; and determination of a way to avoid the target ship. Authors analysed collision avoidance cases of a coastal sea area, which are extracted from an AIS database. The four moments during the collision avoidance manoeuvre, e.g. start time of collision avoidance, is identified with the AIS database. Then, conditions of a give-way and a stand-on ships at the moments are analysed by behaviour analysis. In this paper, the conditions at the start time of collision avoidance manoeuvre is focused. As the result, it is found that the condition at the start time is expressed by a simple equation composed of two parameters: the distance to the give-way and the stand-on ships; and the rate of change in relative bearing to the stand-on ship. Additionally, an assessment diagram to evaluate the collision risk is developed.

In Japan, there are a lot of bridges connecting islands. Particularly in the Seto Inland Sea, several bridges are constructed near the narrow channels. When we pursue the safe operation of the vessels, we consider it important to analyze the masking features of the radar images of such bridges and the reflection intensity.
In this study, we analyzed the features by the difference in the structure and the masking features along the direction of the width of the bridge and the reflection intensity about two bridges, in order to improve the safety of ships traffic.
Conventionally, the radar reflection intensity of a small object such as a small ship has been evaluated by the maximum signal intensity in the image. In this study, we tried a new evaluation method for the radar reflection intensity of the connecting bridges those are huge and strong reflection structures, and we report the result.

In past years, rare marine leisure activities were conducted within Korean water. Korean government currently focus on promoting the pleasure boat activities with the purpose of developing it as the new tourism industry. However, with the increasing of pleasure boat activities within Korean water, more and more marine accidents or collisions between pleasure boats appear gradually. It also brings Korean government the new issue to manage marine activities such as pleasure boats in safe. Actually, it seems insufficient to achieve the captioned purpose only by setting the relevant laws and regulations for leisure boats. Further measures to improve the safety of marine pleasure boat activities should be considered additionally.
Therefore, this paper will discuss ① The current situation of pleasure boats in Korea, ② The comparison to safety policies between Korea, Japan and UK ③ The suggestion to develop Korean marine leisure culture. This paper will also propose the direction to improve safe activities from personal, organizational and governmental aspects respectively.

During the past decade of 2004 to 2014, China has experienced rapid economic development. China's total crude imports increased by around 200 million tons. However the fleets of carrying imported crude oil in China are unable to undertake such tasks due to the small size and old ships. Hence, Chinese government has issued the policy of “national oil fortunes”, and require 85% of the total crude imports should be transported by fleets owned by Chinese ship owners till 2015. Besides, the large scale of ships can also provide a solution to lower the cost for crude oil transportation. The policy-makers also didn't give any guidance for Chinese harbors to face the challenges caused by large-scale trend of ships.
Based on the background and problems mentioned above, this research aims at proposing a solution to lower the cost of crude oil transportation and guarantee the sustainably import of crude oil for China. Meanwhile, we try to find a suitable strategy to settle the large-scale trend of ships. In this research, we find that 231 ships and 11,150 Chinese crews are necessary to fulfill the transportation task. More importantly, the transportation cost per ton will decrease by $3.32. At last, Chinese harbor should speed up the construction of deep-water harbors to accommodate large scale ships.

Various uncertainty factors of logistics exist in actual maritime logistics and these factors should be considered in advance in order to get accurate results. However, it is difficult to consider these various uncertainty factors, therefore, these factors are expressed by fixed value in present studies.
This study develops new optimization methods considering the uncertainty factors of logistics by using robust optimization and multi objective optimization. By using these methods, the uncertainty of transportation volume, ship speed, and oil price are considered and new ship allocation planning optimization system is developed. Thereby, the influences of uncertainty factors are considered and the effectiveness of the developed methods is shown by using the optimization system.

The amount of cargo transportation increases rapidly, and the maritime transportation network has been complicated in recent years. Therefore, the rationalization and efficiency improvement of cargo transportation are required in the international maritime transportation. In this study, a maritime transportation networks are examined by using complex networks and new planning method of maritime transportation networks in consideration of the characteristics of networks is proposed.
In order to realize these, planning of maritime transportation networks is formulated as a multi objective optimization problem considering transportation costs and representative values of the network. Optimization results are compared with the other networks, i.e. Kurokawa network model, and the optimized network models only considering transportation costs and so on. As a result, the effectiveness of the proposed method is shown.

Various information for the vessel traffic management is provided by AIS (Automatic Identification System). Besides dynamic information such as the position etc. the necessary information like destinations and type of ship is included in AIS information. We may improve safety of the vessel traffic at the congested waters by using these information effectively. Therefore, in this study, we decided to think about a system of management using AIS information for the ships which navigated at Tokyo bay.
The distance from the entrance of Tokyo Bay to the inner part of bay is approximately 70km. There are the established routes in Tokyo Bay for ensuring safety of the traffic flow. The management of the traffic and the limit of the navigation waters are operated by VTS (Vessel Traffic Service). Therefore Tokyo Bay is a very large waters, but the navigation route of especially the big ship is almost decided. We established nodes and rinks from the navigation area and we selected the routes from the departure place to the destination. In addition, we standardized the navigation route of the ship based on past AIS data and compared the estimated route with the real route. It was inspected whether we could cope with the prediction of the ship trend. In practice although there is a problem, it is thought that it is effective for future systems construction.

Judging the distance between one's own ship and other ships is more difficult at sea than on land, because landmarks or reference objects are scarce at sea. Although we can now measure the precise distance to an encountered ship using nautical instruments, such as a radar distance indicator or the automatic identification system, ship crews occasionally judge distances by visual observation, particularly in the case of obstacle avoidance. These estimated distances are typically used for making decisions regarding collision risk, and errors might be influenced by experience. In this study, we evaluate errors in the distance to encountered ships estimated by visual observation. Estimated distances were more precise for experienced crew than were those for trainees. There were tendencies to overestimate the distance to encountered ships with increasing ship size, and to underestimate the distance with decreasing actual range. The colour of the ship did not affect the estimated distance. These results may contribute to ensuring safe ship operation.

In the field of marine traffic management, to improve the safety of navigation using AIS target data, the Class B AIS equipment which is not mandatory is available even for small scale vessels. The Class B AIS equipment is simplified, inexpensive, and downsized. In addition, no operator's certificate to operate it is necessary. Class B AIS can also exchange the data with Class A AIS. So far, some system for not only support of ship handling e.g. collision avoidance, but also the other aspect of the AIS data usage is proposed. But the system like that for small craft is not popular yet. So, we start to study about promotion of AIS usage even for small scale vessels. For one of the way to achieve the popularization of Class B AIS, we plan to develop a processing tool to make the application form of tax exemption automatically recorded AIS data. In this paper, implementation of this tool, and the evaluation of its effectiveness are given.

It is essential to maintain the infrastructure after the earthquake. Ships are considered as effective media for transferring people and relief goods to the area where it is very difficult to reach by overland route. For this reason, protecting ships from the Tsunami is very important for saving human life as well as restoration work. In order to achieve this, it is necessary to know the marine traffic condition and find out the area in collision danger when the earthquake is occurred. However, there are few marine traffic studies for this purpose.
In this study, estimating collision course area using OZT (Obstacle Zone by Target) in offshore refugee outside the port is proposed and evaluated its efficiency for reducing collision risks in evacuation from the Tsunami.

The purpose of this study is to analyze the Safety Management Systems (SMSs) for oil exploitation on continental shelves. Prevention of accidents during oil exploitation is critical for the safety of life of those engaged in the operations at sea. Additionally, shipping has become increasingly important for oil exploitation on continental shelves due to development of deep water drilling using Mobile Offshore Drilling Units (MODUs) and shuttle tankers, rather than pipelines, for transporting oil. On the other hand, the international and domestic legal schemes to regulate oil exploitation on continental shelves have not been fully developed and limited to those in specific fields such as protection of marine environment. This study, therefore, aims to specify the needs for safety regulations for oil exploitation by comparing the legally binding multilateral treaties on SMSs applied to shipping and navigation with non-binding Codes and Guidelines on MODUs.
In conclusion, safety regulations by flag state jurisdiction, port state control, and coastal state jurisdiction should be implemented in order to prevent accidents during oil exploitation on continental shelves. A multilateral convention on this issue would be a leitmotif in the near future.

IMO (International Maritime Organization) requires most of the Ocean-going vessels to carry ECDIS (Electronic Chart Display and Information System) by the SOLAS Convention and all the officers to be trained by the 2010 Manila Amendments to the STCW Convention and Code. Nowadays most of the vessels, including not only ocean-going but also domestic vessels, are equipped with ECDIS. It has a wide range of characteristics, such as indication of the ship's position, the heading and the speed through the water, navigation and/or monitoring alert systems in addition to information obtained from traditional paper nautical charts. However, too much information may cause burdens on its users because the size of ECDIS display screen is smaller than that of traditional paper charts. Equipment with a higher degree of usability would provide information more efficiently.
The authors conduct investigation for the usable display system of chart information under geographically and/or environmentally restricted situations. This investigation is aimed at license holders in order to consider a concept of combination appropriate for these situations. In this paper, the authors describe the results of the investigation and propose the concept.

This study proposes the marine navigation support system which provides video images and states around the target vessel. Approximately 80 percent factors of marine traffic accident is human error when we check the report for the last 5 years. Due to the shortage of domestic vessel crew and the human cost cutting, the number of domestic vessel crew has been decreasing and the rate of human error has been increasing. In order to lighten the work load of crew, we designed the system which supports watching from a distant place. Because of taking a high cost, video streaming between the ship and the land is difficult. In this paper, we achieved low delay video streaming at low cost from the cameras which installed at vessel main mast at by mobile data communications. In addition to video distribution, we get the data from nautical instruments and AIS. Owing to display these information on video images, we propose the displaying navigation status system which can grasp the states around the target vessel at a low delay from the land.

Recently relative position of port in Japan has been lower than ports in Asia. Therefore, the number of the fundamental route which calls at a port of Japan are decreasing. Thereby, the problem of the increase in a lead time or the increase in logistics cost occurs.
Then, Japanese government has carried out development policies for some ports in Japan since 2002. But the number of the fundamental route which calls at a port in Japan continues decreasing from 1998.
In this study, we analyze the cause of decreasing of the number of call in the fundamental route of a container service. In addition, we discuss about the case of adding Tokyo port to the existing fundamental route.
As a result, handling time increases by enlargement of a container ship. And in order to maintain weekly service, we found out that it is necessary to increase the number of ships. Thereby, in order to reduce expense, it turned out that a shipping company reduces the number of call and fixes the number of ships.
Moreover, in order to stop a fundamental route at the Tokyo port, it turned out that shortening of handling time etc. is effective.

This research investigates applicability of the two-phase flow MPS (Moving Particle Semi-implicit) method to performance analysis of the OWC (Oscillating Water Column) type WEC (Wave Energy Converter). Estimating detail behavior of an OWC type WEC under any sea state including heavy weather is important for evolution of development of OWC type WECs. Basic applicability and effectiveness of the present method is indicated by numerical simulation of reproducing a coastline OWC type WEC model against a large wave. In addition, arrangement of air particles for setting computational domain is examined. Numerical results about wave impact force analysis by the simulation that air particles are arranged small agree well with the results by the simulation that air particles are arranged full. The result indicates that the present method with pseudo air pressure can reduce computational costs. The full arrangement simulation indicates effectiveness to response analysis of OWC type WECs in the severe wave by the present results including numerical results of response in the chamber. In case of carrying out the small arrangement simulation, suitable boundary condition is required at the end of duct for improving calculation accuracy of response analysis in the air chamber.

It is one the most important things that vessels arrive at the destination safely. Therefore, navigators keep a sharp lookout for safety of navigation. By the lookout, navigators obtain the state of the surrounding and maneuver for avoiding vessels at a proper timing. Navigation support device needs to be without limited action and area using. The transmission type optical head mounted display was used for developing navigation support device by authors. The device of display screen needs to enhance high visibility and to provide information without user's burden. When there is much information for the size of the screen, the user's burden becomes bigger. Thus, this device classified information under three modes and displayed. To improve visibility of screen, we select colors from precedent monographs for screen of head mounted display. In experiment on board, we checked display visibility and confirmed calculated values.

As a pre-survey to tall ship training, the captioned survey collects data in the questionnaires completed by 155 people with experience of joining tall ship training course and thus analyze the educational effects of the tall ship training course accordingly. This analysis is also conducted by the focusing on the words appearing repeatedly in the questionnaire and further study the meaning and educational effects stemming from the mentioned words.
Basically, we can find below words frequently appearing in the questionnaires, that is, nature, training, experience, oversea, tall ship, navigation, funny, memory, works and friends.
However, the word “nature” draws our attentions since it is often mentioned by the different terms in the questionnaires, such as “respects to natures”. The captioned outcome also supports the ideas what the tall ship training course always reiterates until now.