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Article type: Cover
2012 Volume 126 Pages
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Article type: Appendix
2012 Volume 126 Pages
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Article type: Appendix
2012 Volume 126 Pages
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Article type: Index
2012 Volume 126 Pages
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Article type: Index
2012 Volume 126 Pages
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Koji ITO, Hiroaki KOBAYASHI
Article type: Article
2012 Volume 126 Pages
1-9
Published: March 25, 2012
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In the single watch keeping, one of the necessary factors for achieving safe navigation is mariner's competency concerning ship handling. Therefore, shipping companies have carried out the various trainings for masters and officers in order to enhance their competency. When inexperienced marines and experienced mariners execute the necessary tasks in the training of ship handling with the simulator, the behavior characteristics of inexperienced mariners are different from the experienced mariner's one. The mariner's competencies depending on the experience are appeared in the degree of the achieving necessary tasks and the difference of the behavior characteristics. In this paper, the inexperienced mariner's behavior characteristics concerning "Lookout" in the "Nine Elemental Techniques" have been clarified quantitatively, and compared with the experienced mariner's one.
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Kazuki INOUE, Tadatsugi OKAZAKI, Koji MURAI, Yuji HAYASHI
Article type: Article
2012 Volume 126 Pages
11-18
Published: March 25, 2012
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Ship maneuvering simulator (SMS) training is the core of the 3^<rd> grade pilot trainee who had narrow amount of ship-handling experience education and training. They are carried out maneuvering of in the harbor and on the congestion bay area. In this study, authors paid attention to trainees? situation awareness on the congestion bay area and tried to apply the method of Situation Awareness Global Assessment Technique (SAGAT). SAGAT is one of a technique currently used for human interface development of airplanes. We improved SAGAT for SMS and tried to measurement for ship recognition on the bay area and we got the touch that an index to consult with about a learning effect was provided.
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El-Hocine TASSEDA, Kohei OHTSU, Takahiro TAKEMOTO
Article type: Article
2012 Volume 126 Pages
19-29
Published: March 25, 2012
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The consensus among companies and policy makers is that the Standards of Training, Certification and Watchkeeping Convention (STCW) guided training programs for deck cadets are satisfactory and will lead the industry to competency if properly implemented. In this paper, the authors are going to play the role of a whistle-blower by highlighting some shadow areas and pointing out some issues to improve the present training system, and hopefully, shift the focus of the companies from making guidelines and training books to the real monitoring of the onboard training. In this article, by conducting a study on several cases and analyzing onboard knowledge transfer parameters; the authors have concluded that for an up-to-standard onboard training the following are to be re-enforced: Company's supervision by a qualified person; training of the Training Officer to overcome knowledge transfer barriers; and adoption of the 1/3 ratio Concept; 1/3 deck work, 1/3 deck work / bridge watch, 1/3 bridge watch. Finally, the concept of Training Hubs has been introduced to overcome the lack of funding for training facilities and to unify training programs between all training facilities.
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Tomohisa NISHIMURA, Hiroaki KOBAYASHI
Article type: Article
2012 Volume 126 Pages
31-37
Published: March 25, 2012
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The characteristics of collision avoidance for a vessel which is underway in a traffic flow area are compared with the characteristics of collision avoidance in a random traffic area. Here, the traffic flow area does not mean an artificial fairway. It means an area in which a traffic flow is generated by geographical conditions and by the origin and/or the destination of vessels. International Marine Simulator Forum (IMSF) studied the standard characteristics on collision avoidance in a random traffic area in 2006. In this study, the results of lookout to target vessels were analyzed. The authors have also carried out the same kind of experiment. In this study, the authors set a traffic flow in the ship-handling simulator and captains and officers on watch have carried out the scenario and the followings have been verified. In case of detection range of the target, specific differences in each water area have not been appeared. But even if the own vessel is the give-way vessel, they assume that the target vessel in a traffic flow will alter her course along the traffic flow and then they get behind in their judgment on collision avoidance maneuver. This issue results from not seafarers' competence but navigational environment.
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Takahiro TANAKA, Tatsuto YAMADA, Masashi MATSUDA, Atsushi YAMAMOTO
Article type: Article
2012 Volume 126 Pages
39-46
Published: March 25, 2012
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In order to evaluate the maritime traffic system, vessel traffic observation is important for gathering basic data. In recent years, it became easy to grasp behavior or track of vessel by AIS. However, the diffusion of AIS is not high (only approx. 30% around the Kurushima Kaikyo). Therefore, just using AIS receiver to observe the ship which is not equipped AIS transponder is difficult highly. In this paper, it is tried to obtain the vessel traffic flow from RADAR data of Shipborne Voyage Data Recorder (VDR/S-VDR). VDRIS-VDR, which is like the CVR!FDR (what is called Black Boxes) of aircraft, is the data collecting and recording system of vessel equipment's statuses, output and RADAR data. By using image processing and motion analysis for VDR RADAR images, we obtained passing ship's position. As a result, it is shown comparison example of the vessel traffic flow from RADAR data and the vessel traffic flow by AIS.
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El-Hocine TASSEDA, Kohei OHTSU, Ruri SHOJI
Article type: Article
2012 Volume 126 Pages
47-53
Published: March 25, 2012
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Maneuvering a ship in a bend or curved route can be represented as a combination of course keeping and course changing to achieve the final desired course. Significant landmarks and navigation aids are used, by the navigator, to determine when and where to transit between the maneuvers. In this paper, we built an algorithm to investigate the effect of the ship's characteristics and external parameters (navigator behavior) on the turning and curvature radius of ships engaged in a turn in Uraga Suido Traffic Route (USTR), namely at the transition location "USTR - Nakano Se". The Analysis of the curvature and turning radius showed that the Constant Radius Turn is a predominant approach, and that the type and dimension of the ship didn't affect the turn maneuver. It was concluded that the analyzed maneuvers were exclusively affected by the navigator behavior (both Captain and Pilot) rather than the ship's characteristics.
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Yoko UCHIDA, Naoyuki TAKAGI
Article type: Article
2012 Volume 126 Pages
55-64
Published: March 25, 2012
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The present study investigated patterns of foreign accent conspicuous in English produced by native speakers of Chinese. Native speakers of English and Japanese listened to English speech data collected from Chinese-speaking cadets, and reported Chinese accents they heard. Based on their reports, the authors pointed out typical Chinese accents which Japanese speakers are likely to find confusing, with a support of Pinyin transcription and contrastive analyses of Chinese, English, and Japanese. They included realization of English /v/ as [w], peculiar quality of/l/ and /r/ when following a vowel, and insertion of an extra vowel and/or omission of a consonant in a sequence of two or three consonants. China being one of the most important trading partners, we strongly believe that knowledge on characteristics of Chinese accented English described here will help Japanese people in the maritime sector with easier communication with Chinese seafarers, which will contribute to safer navigation of ocean-going vessels.
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Akiko UCHINO, Hiroaki KOBAYASHI
Article type: Article
2012 Volume 126 Pages
65-72
Published: March 25, 2012
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Human error has long been recognized as a cause of trouble and accidents in the maritime field. However, in order to take effective measures to improve safety, it is necessary to inquire further into the fundamental causes giving rise to such human errors. According to some accident investigations, the state where officers don't achieve the necessary tasks for safe navigation often causes dangerous situations. These necessary tasks are determined by changes of navigational situations. Officers have to achieve these tasks, which is indispensable for achieving safe navigation. Therefore, the necessary tasks can be regarded as the workload on officers. The level of workload on officers affects on the level of competency they show. The heavier the workload, the less officers can be relied upon to achieve the necessary tasks expected of them. In this paper, we focus on the necessary tasks for safe navigation, and quantitatively study human errors from the view of the relation between the workload and achieved degree.
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Yoshinori HAMAJI, Nobuo EZAKI, Kunimitsu ISHIDA, Shuji SUZUKI
Article type: Article
2012 Volume 126 Pages
73-79
Published: March 25, 2012
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Recently, because a nautical instrument progressed, the navigational officer don't need to find a position on a paper chart . Because a way of thinking called BRM(Bridge Resource Management) penetrated, an information sharing in the bridge became important. It is important that we use information by organically. Therefore the device which can monitor nautical instrument information anywhere anytime is effective in the bridge. This study investigates the information that a navigation team thinks to be important. Furthermore, we build a system to share information by using a PDA.
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Noritaka HIRATA, Hiroyuki UKITA, Hironori YASUKAWA
Article type: Article
2012 Volume 126 Pages
81-89
Published: March 25, 2012
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Fuliscale trials were carried out to capture the trim effect on maneuverability of a training ship "ToyoshioMaru" with the azimuth propellers which are arranged in parallel at stern part. Turning test and zig-zag maneuver test were conducted in three load conditions with different trim. Three K-GPS antennas were used for measuring 6-DOF motion of the ship. This ship has superior turning performance in any trimmed conditions: tactical diameter is almost 1 .8L where L is ship length when the azimuth angle is 35 degrees. However, the course instability appeared in even keel condition. The instability was significantly improved in the stern-trimmed condition. We found that change of hydrodynamic derivatives with respect to hull drift angle (hull damping forces) in trimmed condition contributes to the improvement of the course instability through the captive model test.
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Ikuo NAKAO, Yasuo YOSHIMURA
Article type: Article
2012 Volume 126 Pages
91-97
Published: March 25, 2012
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Nowadays, various CFD (Computational Fluid Dynamics) methods are used for simulating the flow around rudder or each appe ndage on the h ull. However, turbulent flow in 1 arge Reynolds number cannot be ca lculated easily by numerical method. Then, the turbulent flow models are introduced into the conventional CFD code. DNS (Direct Numerical Simulation) is the method of solving the Navier-Stokes equation directly without any turbulent flow model. Theoretically, it can simulate all turbulent flow. In this study, the flow around rudder and spanker were simulated by DNS. The simulated flow and fluid forces comparatively well corresponded with the experimental results. As the results, rudder and spanker characteristics can be obtained without experiment. This method is e xpected to applying various appendages design such as rudder or spanker.
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Yasuo YOSHIMURA, Ikuo NAKAO, Mamiko KANAMOTO, Mitsuhiro NAKAMURA
Article type: Article
2012 Volume 126 Pages
99-104
Published: March 25, 2012
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Ship's rudder is normally fuliy immersed under the stem. However, the rudder is partially exposed on the water surface in ballast conditions. The manoeuvring prediction in ballast conditions conventionally does not take account of such rudder expose to the water surface. There has been also little research on rudder force in such condition. In this paper, the authors performed open water rudder test in several rudder exposing condition, using a large scale of rudder model. Then the following results are obtained. 1) In the prediction of rudder normal force, the actual immersing rudder area and the effective rudder aspect ratio that is twice value of geometric one should be used taking account of the miler effect of water surface. 2) However, in case of the water that falls down from the face side to the back side when the rudder is slightly immersed, the above effective aspect ratio makes over estimation of rudder normal force coefficient. 3) When the upper top is exposed on the water surface, stall phenomenon does not appear and the maximum lift coefficient significantly increases.
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Kenji SASA, Seiji SHIMIZU, Eishi KOGA, Masayuki FUJII
Article type: Article
2012 Volume 126 Pages
105-114
Published: March 25, 2012
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The Obatake Seto, which locates in the Yamaguchi Pref. in western Japan, is famous for its strong tidal current. It sometimes makes ship navigation difficult. Casualties sometimes happen there because of strong tidal currents and complicated topography. Renewable and environmental friendly energy resources are inevitable to decrease the dependence with fossil fuels or nuclear energy. Authors pay attention the possibility on tidal current electric generation in the Obatake Seto. However, there is very few knowledge on spatial distribution of tidal currents around the Obtake Seto within 100 meters. In this study, properties of tidal currents are clarified through the field observation and numerical simulation from viewpoint of navigation safety and electric power generation.
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Kazusei YAMAMOTO
Article type: Article
2012 Volume 126 Pages
115-122
Published: March 25, 2012
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ISGOTT says that, Experience over a very long period indicates that electrostatic discharges caused by clothing and footwear do not, however, present a significant hazard in the oil industry. This is especially true in a marine environment where surfaces rapidly become contaminated by deposits of salt and moisture that reduce electrical resistances, particularly at high humidity." and "An increasing number of items manufactured from synthetic materials are being offered for use on board ships. It is important that those responsible for their provision to tankers should be satisfied that, if they are to be used in flammable atmospheres, they will not introduce electrostatic hazards." Then the author heard what a seafarer and a land personnel with personal antistatic devices in a tanker discharged. In this paper, the consciousness about seafarer's static electricity by the questionnaire was investigated, and the seafarer's electrostatic potential on tankers was measured. The obtained results are summarized as follows: (1) Human-body electrostatic potential is about Ov with personal antistatic devices, however, it is rarely about 1 kV. (2) Although antistatic measures are implemented by tankers, the two-thirds questioners has felt the static electricity inboard. (3) Antistatic measures are carried out on all tankers by antistatic apparatus and personal antistatic devices.
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Shin HEMMI
Article type: Article
2012 Volume 126 Pages
123-134
Published: March 25, 2012
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The objective of this study is to examine the modern-day meaning and legitimacy of exemption clause in pilotage covenant in Japan by viewpoints of profession's liability and regulation for unfair clause of covenant. Civil law in general takes the principle of liability arising from negligence. According to this principle, negligence shall be decided by investigation to whether breach of duty of due care could be done and damage occurs. Meanwhile, "Exemption Clause" in the said covenant excuses pilot for his civil liability as compensation for damage caused by his default for pilotage contract and negligence to third party, so that pilot is only blamed by own intention or gross negligence. Recent years, however, profession's liability has come into the limelight. Pilot is also the one of professions and he must become responsible for heavy duty of care with contribution of judgments by marine accident inquires. In addition, pilotage exemption clause may be affected by regulation for unfair clause of covenant viewed from law of obligations in civil law these days. Finally, author is sure that exemption clause in pilotage covenant should be revised in the future to liability arising from negligence.
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Mitsuhiro MASUDA, Kuniaki SHOJI, Kiyokazu MINAMI, Koichi MASUDA
Article type: Article
2012 Volume 126 Pages
135-141
Published: March 25, 2012
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The present paper describes the simulation of behavior of mooring vessels in tsunami using the 3-D MPS (Moving Particle Semi-implicit) Method for considering leading wave and backwash effect. The chain of a disaster is brought about by two kinds of tsunami. The chain of disaster means breaking the mooring tether, grounding on a wharf, drift to continental areas, the collision with building by leading wave and the outflow of the floating matter by backwash. In this research, the 3D-MPS method is applied, and the bore like wave is applied as an assumed tsunami. Moreover, expression of the backwash by water pillar collapse is tried. In addition, the vehicle is arranged on a wharf, and the chain of disaster is simulated.
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Takahiro TAKEMOTO, Yusuke SUMIZAWA, Yoshiharu SAKAMOTO, Masao FURUSHO
Article type: Article
2012 Volume 126 Pages
143-151
Published: March 25, 2012
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We need to forge preventive measures that take into account human factors in order to prevent collision accidents. Not only are marine accidents caused by deeply concerning human factors, but many other accidents and disasters are as well. In this study, the authors studied factors that affect human elements on ship operations, and proposed the m-RSHEL Model which expands on the m-SHEL Model by expressing human factors based on the results. In addition, the authors focused attention on R (Human Resource) which is one of the important factors influencing human elements, and discovered the following results by investigating collision accidents that occurred in Tokyo Bay: 1) Personnel The competency to properly use equipment, apparatus etc. for maneuvering, as well as observing SMS and legal restrictions for navigation 2) Manning The manning of sufficient number of navigators who can fully identify and recognize other vessels to ensure safe navigation 3) Training Training that determines and carries out safe distances from other vessels for the navigators of cargo or tanker vessels
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Shinya SHIMOKAWA, Jyunji KAWASAKI, Kenichi SAKAI, Hirofumi MATSUMOTO
Article type: Article
2012 Volume 126 Pages
153-160
Published: March 25, 2012
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This study examined the actual maritime disasters of fishing boats by floating objects based on the fishing boat statistical tables and the accident data. The results are as follows: (1) The maritime disasters by floating objects occurred 15,000 a year for the entire country. (2) The maritime disasters by floating objects for less than 5GT rank fishing boats accounts for 75% of the total. (3) The difference in the maritime disaster incidences in every sea area was clarified. (4) The fishing types involved in the maritime disasters are pole and line, small bottom trawl, gill net and long line. (5) As for the floating objects producing the maritime disasters, driftwood, rope and fishing nets are often found. The injury point is concentrated in the propeller and stem part. (6) The number of accidents depends on the month. It is suggested that the disasters by increase or decrease based on the precipitation or presence of typhoons. In the future, we must think about the connection with other factors about drift occurrence, the process when driftwood, rope and fishing nets flows out and examine the preventive measures effective against maritime disasters.
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Ikumi SUZUKI, Shoji FUJIMOTO, Masaki FUCHI, Tomohisa OHARA
Article type: Article
2012 Volume 126 Pages
161-170
Published: March 25, 2012
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This study describes a result of a survey about understanding marine traffic laws and actions that are taken by small craft navigators. The survey asked small craft navigators what they take into consideration while steering, as well as what they feel about maritime traffic laws. Three points were investigated. The results of the survey showed that small craft navigators don't completely understand marine traffic laws. Therefore there is a possibility that they navigate with a misunderstanding of marine traffic laws. When small craft navigators make avoidance maneuvers among ships, they avoid them at a distance that is shorter than the distance required by ship. It was supposed that how small craft navigators avoid ships at a shorter distance was what made ship navigators uneasy. Furthermore, the survey showed that small craft navigators tend to hesitate when making avoidance maneuvers. Consequently, in order to solve this problem, this study suggests a "special rule" that demonstrates marine traffic laws more simply and easier than existing traffic rules. This "special rule" expects small crafts to take the lead in ship-avoidance maneuvers. In addition, 80% of the surveyed small craft navigators were in agreement with the idea of implementing a "special rule."
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Ulrik Dam NIELSEN, Toshio ISEKI
Article type: Article
2012 Volume 126 Pages
171-177
Published: March 25, 2012
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The paper studies parametric wave estimation based on the 'wave buoy analogy'. The ship motion data obtained from the training ship Shioji-maru are used for the estimation and the results are compared with estimates of the sea states obtained from other measurements and observations. Furthermore, the estimating characteristics of the parametric model are discussed by considering the results of a similar estimation concept based on Bayesian modelling. As a result, it is revealed that there is a distinct difference in the estimation of wave heights and wave periods. This is explained by referencing the concrete modelling procedure of the two approaches.
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Shigeki SAKAKIBARA, Shuu YAMADA
Article type: Article
2012 Volume 126 Pages
179-186
Published: March 25, 2012
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The pneumatic fender roles an energy absorber and spacer purpose for safe ship berthing and mooring in the usage of ship-to-jetty in harbor basin and ship-to-ship oil and gases transfer operations at offshore. In this paper, the velocity factor in performance and its determination procedures are demonstrated by conducting dynamic and static compression tests based on the guideline: 2002 of PIANC. The scale modeling in velocity factor has been clarified for the pneumatic fenders by the compression tests, and the property of the velocity factor has been investigated.
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Masaki FUCHI, Daishiro KUSAKA, Shoji FUJIMOTO, Shinnosuke USUI
Article type: Article
2012 Volume 126 Pages
187-195
Published: March 25, 2012
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Recent investigations have demonstrated that cadet collision judgment times of action for avoiding collisions, as well as their methods for avoidance are inappropriate, and their recognition of distances were incorrect. In this study, we analyzed a cadet educational program for collision avoidance training, its features, and inspected the effects of the program. The effect of the educational program was inspected using a questionnaire. Cadets who participated in a ship training class were divided into a "Control group" and an "Educational group". The educational program was tested using only the "Educational group". The questionnaire was carried out before and after the ship training, and the results were compared. The results suggested the following: (1) The time of collision judgments tended to be influenced by the type of ship that the educational program was carried out in. (2) The educational group was more flexible in their choices for avoiding direction. (3) The knowledge about collision avoidance rules is unrelated to the educational program that we carried out.
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Minh Duc NGUYEN, Kohei OHTSU, Hitoi TAMARU
Article type: Article
2012 Volume 126 Pages
197-203
Published: March 25, 2012
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Ensuring safety of navigation is always a matter of great importance for the ship officers. Thank to the advanced on-board equipments, ship officers now have the access to a huge amount of environment and targets information which can be used to determine a collision avoiding strategy for the own ship. However, maritime accidents are still happening, mostly due to human errors in judging information or controlling the ship, especially in critical cases where he is overwhelmed by the imminent risks of collision. In critical cases, the time allowed for decision making is extremely small and the intention of target ship is unpredictable. The nature of collision avoiding maneuver is therefore similar to the nature of a pursuit-evasion game in which the own ship plays the role of an evader trying to avoid the collision while the target ship is a pursuer who is aiming at causing it. Thence, in this study, the game theory is used to model the collision avoiding problem between the ships as a pursuit-evasion game, taking into consideration the own ship maneuverability. Bacteria foraging optimization algorithm is then applied to seek an approximation of the optimal solution to the problem. Later on, simulation is carried out with an MMG model for the own ship and target motions perceived by radar in Tokyo Bay to verify the method viability.
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Masaaki WADA, Katsumori HATANAKA, Ruri SHOJI, Hirofumi MATSUMOTO
Article type: Article
2012 Volume 126 Pages
205-211
Published: March 25, 2012
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In this paper, the authors present a shared resource platform unifying the tracking information of large vessels and small ships by a database system in order to use it practically and freely for the common purpose. In recent years, the use of the AIS for providing information of a vessel with unique identification, position, course and speed has spread and it makes possible to share the states among vessels at the same time with ease. Besides the monitoring of vessels such that the primary advantage of using AIS, the secondary application has been investigated by restoring information in database. For example, the time series analysis of tracking data has been implemented in the maritime transportation engineering. However, the legal obligation of loading AIS is only limited for the large vessels. Because of that, the recognition of motions of small ships come a large problem in common. Therefore the authors have developed an ubiquitous navigation system for the small ships by correcting position, course and speed through 3G network and began to apply it to some small fishing boats and ferries. In our future, the present technique is going to apply for gathering AIS information of large vessels and small ships which individually corrected now and hope to growth it to the standard platform for sharing resources.
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Ken-ichiro KAWAMOTO, Masaki FUCHI, Kohei HIRONO, Akio TABUCHI
Article type: Article
2012 Volume 126 Pages
213-219
Published: March 25, 2012
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The average age of seaman such as a captain, navigation officer or pilot, is getting higher in Japan. Generally, aging affects our physical function, and it is considered that visual function is also affected by aging. Visual function is the most important factor for watchkeeping at sea, the visual function of seaman, however, is not checked regularly and periodically. We collected ninety-seven data of subjective visual function of seamen by questionnaire to investigate the situation of vision. The results showed that most seamen have some visual function problems, which are predicted by ophthalmological or basic vision study. The averaged number of subjective symptoms was higher in the group of 40s or higher than the group of 20s and 30s, especially, pesbyopia (farsightedness due to aging), visual form perception, contrast sensitivity, and color perception were affected by aging.
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Yukiko YAMAKAWA, Akio IMAI, Etsuko NISHIMURA
Article type: Article
2012 Volume 126 Pages
221-228
Published: March 25, 2012
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Marine container terminal is a switching facility of containers between sea and land as well as between deepsea and shortsea for sea transportation legs. The overall terminal efficiency highly depends on harmonized operations of complicated and different handling tasks being undertaken at the terminal. One of the most important operational issues is the berth allocation scheduling (or berth allocation problem), because an improper berth schedule forces ships to be berthed far from their containers to be handled in a yard. Such an unproductive service situation is never able to be overcome by any proper operational efforts for other handling tasks. The authors developed heuristics that were implemented using a subgradient optimization technique with a Lagrangian relaxation to the original problem for the dynamic berth allocation problem in discrete locations. This study improves the heuristics by introducing a new procedure to find a better feasible solution in the entire iterative process of subgradient technique.
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Lisa SUZUKI, Hisayuki KUROKAWA, Saburo TSURUTA
Article type: Article
2012 Volume 126 Pages
229-236
Published: March 25, 2012
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Currently, global warming is a globally serious problem. And also in marine transportation, reduction of greenhouse gas (especially carbon dioxide (CO_2)) is needed. So, IMO discuss to reduce the measures carbon dioxide emissions. But, all their measures are limited to marine transportation. In order to reduce carbon dioxide emissions on a global scale, it is incomplete that only an effect on marine transportation is considered. That is to say, it is necessary that effects on land transportation and production are considered. Therefore, this study examine for wheat import of our country the relations between carbon dioxide emissions in marine transportation and other origin of carbon dioxide emissions (land transportation and production) as an example concentration of ports.
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Kazuyoshi MAEKAWA, Seiichirou CHIBA, Hiroki YASUMA, Nobuo KIMURA
Article type: Article
2012 Volume 126 Pages
237-243
Published: March 25, 2012
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It is known that a loading condition of fishing vessel changes frequently with fish catching and fuel oil consumption. This paper describes the study on influence of loading condition on drifting motion of fishing vessel in a regular wave. To investigate the influence, model experiments to measure hydrodynamic forces and wave drift forces acting on a hull in various loading conditions were carried out. Based on the characteristics of the forces, the results of drifting motion test in a regular wave were examined. As the results, it was found that the trim condition of vessel affects drifting motion significantly. Therefore, it is important to consider the trim condition of vessel for the prediction of drifting motion.
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Yoichi SHIMADA, Shigeaki SHIOTANI, Keiko TAKAHASHI
Article type: Article
2012 Volume 126 Pages
245-253
Published: March 25, 2012
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We compare wave model results (the same model setting except for wind data) in the North Pacific using different wind reanalysis data, ECMWF 40-year Reanalysis (ERA4O) and NCEP/NCAR Reanalysis (NCEP). The wave model results in the central and eastern region of the North Pacific using wind reanalysis data from ERA4O and NCEP correspond well with the observation, respectively. On the other hand, the model results in the Japanese coast do not correspond with the observation worse than those in the central and eastern region of the North Pacific. The monthly mean difference of significant wave height from these wave model results using different reanalysis wind data is significant from the Japanese islands to the Alaska offshore region. Some of monthly correlation of significant wave height between these wave model results shows low correlation region from the Japanese islands to the Alaska offshore region. These suggest the dependency of reanalysis wind data on the wave model in the region from the Japanese islands to the Alaska offshore region.
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Miho NISHIDA, Yasuo YOSHIMURA, Yoshiaki KUNIEDA, Shigeki IKEDA
Article type: Article
2012 Volume 126 Pages
255-263
Published: March 25, 2012
Released on J-STAGE: January 15, 2017
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There are many serious accidents such as aground or ship's broken that is caused by the anchor dragging and often bring many loss of crew when ships are anchoring in a heavy storm. The captain has to decide whether the anchoring is suitable or not in such condition. For this purpose, it is required for him to predict the maximum mooring force properly and confirm that the predicted force is enough for the anchoring. In order to realize such prediction, the authors carried out the experiments using several ship models and clarified the characteristics of mooring forces for various wind force and waves. Then the simple prediction methods of the maximum mooring force as well as the average mooring force have been proposed here based on the experimental and theoretical approaches. The predicted horizontal mooring force agrees well the experimental results.
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Brahim MEZAOUI, Ruri SHOJI, Hitoi TAMARU, Hisaki NISHIYAMA
Article type: Article
2012 Volume 126 Pages
265-275
Published: March 25, 2012
Released on J-STAGE: January 15, 2017
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When planning a transoceanic voyage, ships weather routeing is a valuable tool, which using an optimization method can help achieve different objectives. The accuracy of the generated optimized route depends on a large degree on the range and accuracy of the forecasted weather data that is necessary to describe the evolution of the weather conditions throughout the voyage. With the development of the ensemble prediction system, a new source of weather information for relatively longer times became available. In this study, the usability of the one month wind ensemble issued by the Japan meteorological agency is investigated. Simulations were carried for three transoceanic routes that take over 16 days, using various weather inputs; traditional routeing methods are compared with the use of the ensemble mean and its combination with the traditional deterministic forecast and both methods are scored against the most optimal route obtained by the use of the forecast analysis. Results show that the use of the mean of the ensemble forecast may help achieve voyage times closer to the optimal ones, and the spread of the routes generated by using different weather inputs can give an idea about the certainty of the obtained route.
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Heffry Veibert DIEN, Hiroki YASUMA, Yasuzumi FUJIMORI, Nobuo KIMURA
Article type: Article
2012 Volume 126 Pages
277-282
Published: March 25, 2012
Released on J-STAGE: January 15, 2017
JOURNAL
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A study of coastal fishing boats (small purse seiners) was made in North Sulawesi province, Indonesia. The goal of this study is to clarify the rolling motion under fishing operation of the small purse seiners. First of all we examined the boat form of the purse seiners and practical conditions of rolling motion under fishing operations. Based on the data, the characteristics such boat's stability and rolling motion under fishing operation were calculated. The results of the analysis are as follows: the boat types were relatively slim around the hulls, and the boats had the round shape under water, and a boat still used by fishermen had extremely poor stability, and the roll angle increased remarkably in stage when the boat crossed the wave direction with hauling process, and results of Wavelet analysis showed that the purse seiners used in North Sulawesi had the same characteristics of rolling motion, and wavelet coefficients became large in hauling process.
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Yasuyuki NIWA, Hisaya MOTOGI, Chihiro NISHIZAKI, Takahiro SETA
Article type: Article
2012 Volume 126 Pages
283-288
Published: March 25, 2012
Released on J-STAGE: January 15, 2017
JOURNAL
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Recently, Ship-to-Shore radiocommunication systems, such as the maritime broadband system, give safety and efficiency navigation supports to mariners and operators like the weather routing services. Furthermore radiocommunication system between ships is being developed. Exchanging navigational hazard information between encountered ships, such as appearances of fishing vessels, drift timber and whales, would be beneficial for keeping navigational safety. We have focused on wireless LAN for radiocommunication between ships. In preceding field trial, we used omni-directional antennas and measured a few hundred kbps throughput between ships, which was slower than our target. This time, in order to get faster throughput, we carried out a radiocommunication field trial again and used directional antennas. The trial was done by sailing a ship along the heading line of another ship moored to a pier. We measured RSSI (Received Signal Strength Indication) and throughput between ships at the same time. As a result, we confirmed 2-path model affected by the reflection of the sea surface, but the measured throughput was enough to our expectation.
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Article type: Appendix
2012 Volume 126 Pages
App3-
Published: March 25, 2012
Released on J-STAGE: January 15, 2017
JOURNAL
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Article type: Cover
2012 Volume 126 Pages
Cover2-
Published: March 25, 2012
Released on J-STAGE: January 15, 2017
JOURNAL
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