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Article type: Cover
1999 Volume 101 Pages
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Published: September 25, 1999
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Article type: Appendix
1999 Volume 101 Pages
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Article type: Appendix
1999 Volume 101 Pages
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Article type: Index
1999 Volume 101 Pages
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Article type: Index
1999 Volume 101 Pages
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Chunming FAN, Akio YASUDA, Hiromune NAMIE, Masashi KAWAMURA
Article type: Article
1999 Volume 101 Pages
1-5
Published: September 25, 1999
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A regional positioning system is proposed, composed from two geostationary satellites, the center and mobile stations. TDMA (Time Division Multiple Access) satellite communication system is used to transmit the position data of satellites and synchronize the clock of the mobile station with that of the center station in order to find the absolute ranges to the satellites. The TDMA communication helps to keep a rough synchronization with the clock of the center station. The mobile station sends a signal to require the synchronization and the center station answers it with the time difference measured there between the both stations to make the precise clock synchronization. The authors evaluate the accuracy of time synchronization to be about 10ns by the data once measured between VSATs (Very Small Aperture Terminal) of the both stations. Then they evaluate the positioning accuracy of ship to be less than 28m when measured on the Japanese Islands and in the surrounding waters.
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Masashi KAWAI
Article type: Article
1999 Volume 101 Pages
7-14
Published: September 25, 1999
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It was tried to investigate the relations between meteorological elements and post-fit range residuals for discussing the causes of the 12-hour and 24-hour period fluctuations in post-fit range residuals in orbital analysis of geosynchronous satellites. The results of the investigation are as follows. (1) There is a correlation between 24-hour period fluctuations of residuals and relative humidity variation. (2) A 12-hour period fluctuation of residuals appears clearly, when the relative humidity scarcely changes. (3) There is a correlation between the 12-hour period fluctuations of residuals and tidal generating forces. It was shown that the 12-hour period fluctuations of residuals could be explained only under the assumption that the tracking station moves horizontally with earth crust. It is considered that there are horizontal flows of asthenosphere which are induced by tidal generating forces, and the earth crusts moves horizontally with the flows in the mantle such as ocean currents and tidal currents. It is estimated that the observed range to CS-3b increases by about one meter with 20 percents increase of the relative humidity.
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Takeyasu SAKAI, Kazunobu KOREMURA
Article type: Article
1999 Volume 101 Pages
15-20
Published: September 25, 1999
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DGPS (differential GPS) enables realtime positioning accurate within a few meters. DGPS user equipments receive, in addition to ranging signal from GPS satellites, correction information generated at and transmitted from a reference receiver station fixed on the ground. Recently some DGPS networks are available which broadcast correction information to users being in the coverage. In general, users select the nearest single reference station out of two or more available stations. Because of its dependency on the relative location between user and reference station, DGPS positioning accuracy might be improved by using correction information of multiple reference stations. We will explain the method to apply multiple correction information simultaneously to the correction algorithm, and show experimental results that indicate the effects of using multiple reference stations. It will be shown that weighting to each reference station by the distance from user receiver is effective for long baseline distance, but has little effect for short baseline.
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Manami IDE, Shogo HAYASHI
Article type: Article
1999 Volume 101 Pages
21-27
Published: September 25, 1999
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A radar as a nautical instrument is indispensable for navigation. Now, the original of radar function is changing from a positioning long range to a steady detection in short range. In these decade, it is important to surely detect a small target for short range. Furthermore, the target identification will be required. Many instruments or system would be tried for individual identification. In air traffic region, transponder system is very popular and well-known. It, however, do not come into wide use for identification of each vessel. A transponder for marine have been used for special purpose only. In this paper, new concept of the transponder with frequency shift is proposed about detection and identification for marine wide use and shown some results of trial observation.
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Tatsuto YAMADA, Akira NAGASAWA, Asao NISHINO
Article type: Article
1999 Volume 101 Pages
29-36
Published: September 25, 1999
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This paper is intended as an investigation of the evasive area around a ship which a navigator would like to keep free with respect to other ships as defined by Ms. Goodwin. Authors assume that the boundary of the evasive area is an ellipse around a certain ship and the distribution of ship's paths is a normal distribution. From both of the theoretical considerations for the evasive area and the radar observations in the KANMON Strait and the KURUSHIMA Strait, it was confirmed that the density distribution of the relative positions of the following ships was represented in the normal distribution with changing σ according to the distance from the preceding ships. Furthermore, it became clear that there was a difference in the size and the shape of the evasive area between the above two observation areas.
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Dongping ZHOU, Hayama IMAZU
Article type: Article
1999 Volume 101 Pages
37-45
Published: September 25, 1999
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This paper is concerned with the research on the relationship between ship's encounter situations and traffic density, especially pay particular attention to the relationship between multiple encounter and traffic density. The encounter situations are divided into simple encounter and multiple encounter, in this paper the multiple encounter is defined when two or more than two targets are involved in the situation simultaneously and divided into same multiple encounter and different multiple encounter. Simulation was performed in random traffic condition that could be easily adjusted with traffic density. First, the encounter situation from the viewpoint of each ship was analyzed. Then the encounter combinations between the ships that involved in one encounter situation were classified according to their respective encounter situations, and the ratios of the combinations in various densities were obtained. Also through the simulation method, this paper certified the result that the ratio of the multiple encounters to the total encounters is proportional to density, whereas the number of encounters is proportional to the third power of density. Finally, using actual traffic data of Uraga channel and its vicinity in Tokyo Bay investigated in 1994, the encounter situations in Uraga channel where traffic flow are restricted by regulation rules were compared with those in random condition.
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Takahiro TANAKA, Kinzo INOUE
Article type: Article
1999 Volume 101 Pages
47-53
Published: September 25, 1999
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A ship needs a course line in order to perform navigation safely and efficiently. If we could set a suitable course line automatically, it would relieve burden of the navigator and reduce maritime casualties such running aground. In this paper, the author proposes a method to set a course line from the shape of available water area. The procedure of this method is as follows : 1) Select the available water area 2) Extract the Medial Axis from the available water area, and assume the network on it 3) Calculate the shortest path between the origin and the destination, and calculate inscribed radii of points that form the Medial Axis 4) Pass the shortest path through the filter that utilizes the inscribed radii Utilizing this simple method, some examples of course line on practical water area are shown. As a result, it was found that the method is useful on restricted water area such harbors and narrow channels. In addition, the method could be applied to estimation of the water area network.
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Yusuke YAMAZAKI, Yoshio MURAYAMA, Makoto ENDO
Article type: Article
1999 Volume 101 Pages
55-63
Published: September 25, 1999
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A result of the accident investigation should be needed to get clear causes for the prevention measures. Many factors are related mutually in marine casualties. Multivariable Contingency Analysis is the most fundamental method to examine the participation of other factors in the connection that factors are mutual. Using the data made by Marine Disaster Agency, authors made analysis by the method and could make sure of that the method is useful for the investigation of marine casualties, and got a following result. The cognition error has the relation to the factors as "single watch", "auto-pilot", and "night time". This result stayed with having made well-known facts clear quantitatively, because investigation items of data were short. It is not easy to get detailed data that shows the truth of the casualty. And, authors consider that it is effective to analyze the incident data by this method.
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Tsukasa NAGAHATA
Article type: Article
1999 Volume 101 Pages
65-73
Published: September 25, 1999
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This report deals with the definition and consideration of "casualty distance" and its applications to marine disasters. Casualty distance is the interval from the base line drawn by a coast or center buoys to a casualty point obstructing marine traffic. The distance is the similar to the time headway of cars or ships in traffic engineering, which has two characteristics : the exponential distribution and Poisson's one. They were confirmed by comparing the calculated results with the actual conditions in the Uraga Channel and Shikoku-Shionomisaki coastal regions. These characteristics can be also applied to the survey and analysis on marine casualty by showing some numerical illustrations of the marine accidents requiring rescue in Japan and the passage widths at Urage Channel.
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Seiji IWAMOTO
Article type: Article
1999 Volume 101 Pages
75-82
Published: September 25, 1999
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Automatic control systems of ships have actively been investigated from verious viewpoints in many institutions since 1980's. However, there are many problems to develop the system, for instance, problems of harbor facilities, variety of ships and its dynamic characteristics, disturbances, control systems, and so forth. In this study, a design method of the automatic control system that is combined with decoupling control, one of results of the modern control theory, and the conventional control theory is investigated. As an example, by selecting propeller and bow and stern thrusters as manipulated variables, ship speed, lateral shift displacement and heading angle as controlled variables, the design method of an automatic control system for berthing manoeuvring is proposed. Its effectiveness is examined by computer simulation, and the possibility and problems as an automatic control system of berthing manoeuvring are discussed.
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J. A. PINKSTER, Hideki HAGIWARA, Ruri SHOJI, Hitoi FUKUDA
Article type: Article
1999 Volume 101 Pages
83-93
Published: September 25, 1999
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In this study, a simple dynamic positioning (DP) system which is called "weather vaning DP system" has been developed. This DP system uses only controllable pitch propeller of the main engine and bow thruster driven by the PID feed-back plus wind feed-forward control algorithm to position the reference point on the vessel at the specified point on the earth. The system possesses automatic weather-vaning properties, i.e. the heading of the vessel is not controlled by the system but governed by the environmental conditions. The onboard experiments of weather vaning DP system were carried out in December 1998 using the training ship Shioji Maru of the Tokyo University of Mercantile Marine. The main results of the experiments are as follows. (1) In weather vaning DP system, the stable equilibrium condition is obtained when the ship's bow points to the wind (or current) direction, which makes it possible to perform accurate DP with small thrust of the bow thruster. (2) The wind feed-forward control is very effective to reduce the lateral motion of the vessel in a strong wind condition. (3) The differential feed-back control is inevitable to perform the stable DP. (4) The stability of weather vaning DP deteriorates as the reference point is moved aft from the bow ; the DP is stable when the reference point is put forward of the bow. The experiments to pursue the specified point moving on a square and semicircles were also carried out, and it was found that the control algorithm of weather vaning DP was applicable to the automatic tracking.
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Hideo YABUKI, Noriyuki SASAKI, Yasuo YOSHIMURA
Article type: Article
1999 Volume 101 Pages
95-102
Published: September 25, 1999
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A full-scale experiment has been performed to compare each stopping ability of both a ship with a controllable pitch propeller (CPP) and one with a fixed pitch propeller (FPP). The test ship is 5, 884 G.T. with a single CPP and has a direct reversing system for her diesel engine as well. Stopping tests were carried out for various J_<s0>(=U_0/(n・P)) in both the CPP and FPP operation modes. As a result, in the range of the maneuvering speed, stopping time and distance in the CPP mode have mostly shown shorter than those in the FPP mode, so that a CPP is superior to a FPP in its stopping ability. In the meantime, in case of the test ship on reverse maneuver, her turning motion in the CPP mode proved less stable than that in the FPP mode and the degree of the motion increased in proportion to |J_<s0>|. During on stopping maneuver of a single CPP ship in harbor, it is therefore recommended, in order to reduce her turning motion, to proceed with minimum ahead pitch and to apply a little higher reversing pitch than in the case of a FPP ship operation.
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Yasuyuki NIWA, Masayoshi NUMANO, Junji FUKUTO, Youji MUROHARA
Article type: Article
1999 Volume 101 Pages
103-108
Published: September 25, 1999
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Kurushima channel is one of the most difficult channels for ship navigation, because of the narrow width of the channel, the unique traffic rules and the strong and variable tidal current flows. Authors surveyed the tidal current flows and ship movement at the same time at the passage area of Kurushima channel by the observational systems of Yuge-Maru August, 1998, and analyzed the effect of the current on ship speed. Results are summarized as follows : When it was just before and after turn of tide, in spite of small current speed, ship speed is lower than theoretically estimated speed. At that time the current was observed as unsteady, so we consider this is the reason why ship speed was lowered. When it was the time that the current was the strongest, ship speed was around the theoretically estimated speed. At that time the current was quite steady and ship speed was, therefore, not lowered.
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Hiroyuki SADAKANE, Chol-Seong KIM
Article type: Article
1999 Volume 101 Pages
109-114
Published: September 25, 1999
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The wheelhouse front glass of a fore-bridge-ship had been destroyed by the shipping of water in rough sea, and the ship had fallen into uncontrollable conditions for ship handling. The above destruction was an unbelievable fact for us because the front glass was in a very high position (about 20m) above the water surface. In this study, we carried out the water tank experiment using a model ship and regular waves, and observed the appearance of the shipping of water and the behavior of the shipped water flow by using video-cameras. And also the speed of the flow destroyed the front glass was tried to analyze from video-pictures. The obtained results are as follows : (1) The water shipped from the fore end and both sides of the bow was concentrated on the centerline of the deck and flew toward the bridge like a rushing stream with ample quantity. (2) After collided with the bridge, the rushing stream ran up forcefully on the front face of the bridge. In this case, this flow did not flow along the vertical slope of the bridge wall but ran up with a rather lower angle than the above slope. And finally the stream crashed directly into the front glass part. (3) Such rushing flow clearly occurred in the condition to be the wave steepness H/λ over about 1/10 and the wave length/ship length ratio λ/L over about 1.0. (4) According to simple analyzing method, the flow speed at the front glass height was 3〜3.5 times as fast as the velocity of the surface wave elevation.
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Nobuo KIMURA, Kiyoshi AMAGAI, Tsukasa HOKIMOTO, Toshihiro IWAMORI
Article type: Article
1999 Volume 101 Pages
115-120
Published: September 25, 1999
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The safety of the small fishing boats in the rolling motion is extremely harmed if the shipping water should occur. The external force generated by the fishing operations promotes such loss of the safety. Also, the condition of the fishing boats like the loading changes in short time generally. To know accurately the wave condition for the shipping water occurrence, the improvement of the evaluation for safety of the fishing boats in. fishing operation has been obtained. In this paper, we took notice of the application of the Neural Network model to the forecasting of the shipping water occurrence. Based on the 4 input variables by the tank tests ; wave height, wave frequency, loading value and angle of inclination due to the tension with culture facilities, we applied the Neural Network model for the forecasting of the shipping water occurrence. And then, using the forecasting model, a boundary surface on wave conditions for the fishing safety has been obtained.
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Shunsuke TAKAOKA, Yujiro MURAYAMA, Masayoshi KUBO
Article type: Article
1999 Volume 101 Pages
121-130
Published: September 25, 1999
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It is required that the ship preserves the environment in the marine transportation. In this meaning, recently, the necessity of the sail equipped motor ship has been increasingly recognized. However, there is a problem that the equipped sail brings poor maneuverability of the ship. To improve the maneuverability, five kinds of the following automatic sail control modes were developed. (1) Ahead moving control, (2) Turning control, (3) "Heave to" control, (4) Astern moving control, and (5) Side moving control. The maneuvering simulator with the two dimension display which incorporated these control modes was developed. The ability to control of the five kinds of the control modes in pure sailing under the constant wind was discussed in the preceding report. In this paper, the ability to control of the ahead moving control mode and the turning control mode with the engine assist under the change wind is discussed. The simulation results show some improvement in the ship maneuverability of the sail equipped motor ship with the automatic sail control modes. It is found that the sail shaft rotating speed is required to be more than 5 deg/sec.
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Hideshi TSUKAMOTO, Eri MURAKAMI
Article type: Article
1999 Volume 101 Pages
131-136
Published: September 25, 1999
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We made a system of view from ship. Views by this system are different from the one which had been used. An arbitrary position (viewpoint) and visibility can be set. Moreover, not only daytime but also the view from ship in nighttime can be made. The view in nighttime does not display features ahead of a ship, and display light color and its blinking pattern of the lighthouse and light buoy. This system is executable by the personal computer. The price is low for the ground height data set which this system used, and obtaining is easy.
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Shigeaki YADA, Hisaaki TAKAYAMA, Shiho MATSUDA
Article type: Article
1999 Volume 101 Pages
137-142
Published: September 25, 1999
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According to the marine disaster agency, one of the most significant causes of collisions is the failure of lookouts and failure to sound warnings with the ship's horn. Under current regulations vessels of less than 12 meters in length are not required to have a horn. In the current study we examined the effect of using different types of beep sound for small vessels. The results are as follows : 1) The acoustic beep sound that we used in this experiment was divided into continuous wave and impulse wave tones. The decay difference of acoustic pressure by spacing becomes that difference of reference tones of spacing one meter because the coefficient of revolution expression to show decay by spacing of continuous sound of waves is equal. 2) There were three kinds of beep sound which showed not less than 70dB by spacing 50m, and it was sequence of Gong, Can and Whistle. 3) We found that the most significant sound for the small vessels is the Whistle when considering other factors of carrying nature, which used five kinds of beep sound.
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Mina SAKURAI, Masao FURUSHO, Kunishige NITTA, Tadahiko FUKUDA
Article type: Article
1999 Volume 101 Pages
143-149
Published: September 25, 1999
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The visual perception of targets at sea by ship operators is one of the very important factors for safe navigation. Therefore, it is necessary to analyze the visual characteristics at sea with special environment compared with land. In this research, attention was paid to the color discrimination capability that is one of the characteristics of color perception. Following results were obtained by the experiment using an ND 100 hue test. 1) At twilight time, the color discrimination capability declined compared with that at daytime. 2) In the case of fine weather in daytime, color discrimination for example "yellow", was excellent compared with other colors. 3) This tendency faded with the approach of twilight until full darkness.
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Hideo USUI, Kinzo INOUE
Article type: Article
1999 Volume 101 Pages
151-160
Published: September 25, 1999
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Sufficient arrangement of anchorage at a harbor is supposed to estimate harbor capacity for anchorage. But there has been no research on this sort of estimation. This paper proposes a method to estimate the maximum permited number of ships to anchor at the place defined in terms of mariner's mind, and another way of estimating it, easier one by using the Monte-Carlo method, without considering mariner's mind. Through these propositions, the relationship between these two methods is made clear.
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Masayoshi KUBO, Hiroyuki MINAKAMI, Yosikane MURATA
Article type: Article
1999 Volume 101 Pages
161-171
Published: September 25, 1999
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It is reported that local ports are under severe conditions in a sense of low workability. We carry out some researches on cargo handling volume of containers, number of cranes, kinds of berth and unused area in port. The obtained results are summarized as follows. (1) A characteristic of the local ports is cleared using a relation between the cargo handling volume and number of enterd ships. The local ports are classified into two groups, one has 1/3 of the handling volume per ship of major ports, and the other has 1/5. Moreover, the frequency of enterd ship tonnage for each port are also classified into 3 groupes. (2) It is well-known that the handling volume in the local ports is small. On the other hand, the possible handling volume can be calculated to be about 100, 000TEU. Using these data, we present a remaining volume for each port. It can be used for the future target for the port revitarization. (3) The unused ares for each port can be summarized, the low-used area however are hard to research. We present the ratio of the berth usage as an alternative index of the low-used area. (4) It is shown how the unused area are diverted as a short term temporary usage. (5) In the existing construction of port, the publicity is regarded as more important than the payability. So it is hard to show the lowest handling volume from the payability. If the lowest volume is calculated from the construction costs, it is clarified that it is approximately 70, 000 TEU/year.
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Masayoshi KUBO, Shinji MIZUI, Hidetoshi TACHIBANA, Yasuo SHIMIZU, Masa ...
Article type: Article
1999 Volume 101 Pages
173-180
Published: September 25, 1999
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Many harbors have been constructed facing the open sea in Japan. In a busy season, the shipping activities are often interrupted due to strong winds and heavy seas. However, these severe situation have not been recognized due to limited information. We developed real-time wave measurement system and carried out a field observation of the waves using this system under winter condition. The purpose of this study is to forecast waves near harbor entrance with the observed data on the wave height and current. The results obtained from the study are summarized as follows: (1) The Fourier Transform method is effective to estimate the fixed point waves near harbor entrance similar to the hindcasting method. (2) It is possible to forecast the waves near harbor entrance by the Multiple Regression Analysis. (3) Especially, the said analysis method is useful for forecasting the period of waves near harbor entrance.
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Mitsuo TADA, Hideshi TSUKAMOTO, Hideki AKIYAMA, Sumitoshi OGATA
Article type: Article
1999 Volume 101 Pages
181-187
Published: September 25, 1999
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The tidal front formed in heating period was surveyed in the sea area southern east of the Kurushima Channel, Japan by CTD every month from April to October, 1998. The flow structures of the tidal front were observed by ADCP in June, 1998. The following results were obtained; 1) The tidal front was located at about 5 or 6 miles apart eastward from the east entrance of the Kurushima Kaikyo Traffic Route on the observation line in the last period of flood. 2) Existence of the bottom enhanced topographic eddy at the rearward of the shoal was suggested by the tidal flow patterns and the shapes of tidal front.
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Yoshiaki SATO
Article type: Article
1999 Volume 101 Pages
189-200
Published: September 25, 1999
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The use of national flags by ships is limited only to its nationals except when it is employed in time of war to escape capture by enemy vessels. It is expressly permited to foreigners by the British Shipping Act of 1894, Sec. 691 and the present Japanese Vessel Act, Article 22, Clause II. In spite of somewhat misleading interpretation by Japanese municipal lawyers to take caputure for arrest in time of peace, these stipulations have the same origin found to be traced back to the French Maritime Ordinance of 1650 which prescribed for French captains not to hoist other banners than France's while waging war. In the days of this ordinance French marines were too weak to engage war on the sea. Besides the exceptional and rare ships which the Admiral fitted out at his own expense, available were only privateers armed by private persons. Their greed for gains forced themselves to neglect sufficiency of armament during wars and exposed the flag of France to insult very often. Harsh pillage was committed even after truce to the detriment of the honour of the king of France and his allies. This state of affairs led to the above mentioned ordinance to bring order to naval wars. But approximately after 1681 ordinance of France it had been almost always permited for the privateers to keep aboard any flags which they judged as proper and to use them when driven by necessity in order either to recognise better the ship they encountered or to escape the pursuit by enemy which they assumed stronger than themselves. What was prohibited was to attack under false flags or colours and mainly concerned privateers, for they were the first to disguise their nationality as a ruse of war. War ships were, as it was expected, the last to hide their nationality to avoid battle with enemy war ship or to attract merchant ship apparantly fragile to resist. It is so natural for this ruse of war to authorise victim of privateers to do the same thing. For a long time this custom could have been maintained without considerable trouble. So long as the speed of war ships was slow and their range was short, no fatal surprise could threaten. A suspicious ship could be observed long before it became dangerous. There was wide room for merchant ships to escape and enough time to make preparation for the combat. Even if a false flag enabled an enemy to approach and fire, the first attack could be rarely fatal. Modern weapon can fataly attack targets beyond visual range or even over the horison where it is impossible to confirm that the target is a legitime military object. The maintenance of this ruse of flag greatly increase the danger to neutrals which Japan has much possibility to become in future armed conflicts. In 1915 the U.S.A. protested the British ship, the Lusitania, wearing American colours in the war area. Strongly worded protests were also presented to Britain from the Netherlands and the three Scandinavian states. Their common ground was that this old rule had become obsolete. It is difficult to see why the law of the sea should continue to tolerate method of deception originating from privateers'discretion of oppotunistic choice between assaulting the weak and retreating from the strong. We need not go so far as dealing all aspects of ruses of war concerning ships. What can be and what should be done is to deplete the exemption clause of the Article 22 of the Japanese Vessel Act to keep free hand in our diplomacy.
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Kuniaki SHOJI, Tokiko TAKABAYASHI
Article type: Article
1999 Volume 101 Pages
201-209
Published: September 25, 1999
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In these years many bridges and offshore structures have been constructed near ship's waterways. Examples of these are Seto Bridge, opened in 1988; Tokyo Bay Crossing Bridge-Tunnel, opened in December 1997; Akashi Kaikyo Bridge, opened in April 1998; Bridges of Onomichi-Imabari route (Shimanami Kaido Bridge), opened 1st May 1999. Owing to the increase of bridges and offshore structures as well as marine traffic, ship collision accidents with these structures have been increasing. To keep safety from ship collision accident with such structures various kind of protective device are used. It is necessary to estimate the strength of ship in order to design these protective device. In this paper the authors have introduced a simplified formula for calculation of ship bow strength based on relation between various ship dimensions. The effect of 16 dimension related parameters has been studied in this work. No remarkable variations were found between dimension related parameters of recently built ships and earlier ones. Results of calculated ship bow strength were compared with model experiments. Both results were in good agreement. In addition to the above calculation, entrance angle, colliding height and so on were also studied by using this simplified formula.
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Shigeo MITA, Kuniaki SHOJI, Chisato NONOMURA, Kenichi FUNAKI
Article type: Article
1999 Volume 101 Pages
211-218
Published: September 25, 1999
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The pelprene protective device is made from polyester elastomer and the shape of the cross section is cell structure of honeycomb type. Recently, we are doing the research that checks the characteristic of the protective device by the model experiment and numerical analysis and used the urethane foam as a model. In the previous paper, we discussed the characteristic of the time that the ship penetrated into urethane foam statically. These results almost agree with the numerical analyses and experiments. In the present paper, we report about the research result in the time that investigated it about pelprene protective device. The following results are obtained. (1) When the entrance angle of the bow becomes big, the slope of a reaction force-bow penetration curve becomes steep. At this time, the change rate of the slope becomes steep with the increase of the entrance angle. This characteristic is the same as in the case of the urethane foam of micro cell structure. (2) We tried the estimation of a reaction force-bow penetration curves by calculation. These results agreed almost with the experiment results.
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Masayoshi KUBO, Kenji ASAKI, Kazusei YAMAMOTO, Yoshio NISHINO
Article type: Article
1999 Volume 101 Pages
219-226
Published: September 25, 1999
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To investigate the possibility of preventing spilt oil diffusion by Oil-Curtain and factors relating to the performance of containing spilt oil under rough weather condition, some model experiments are carried out. In the experiments, a tanker model of 318cm length which is enclosed with a curtain made of a vinyl sheet of 0.1mm thickness is set in a towing tank and the behavior of the curtain and contained oil are observed in beam sea. From the experiments, following results are obtained. (1) When height of waves becomes higher, the change of the curtain shape goes through the similar stages for various wave periods and quantities of contained oil. (2) Limit height of waves to contain oil becomes the minimum when Tr/Tw nearly equals to 1, where Tr=rolling period of a ship with the curtain, Tw=wave period. (3) A side at which contained oil passes under the curtain depends on the phase difference between the rolling and the heaving. (4) A relative heeling angle against wave surface is one of the limit value to contain oil with-in the region enclosed with curtain. (5) The experimental results suggest that it is possible to improve the performance to contain oil by adjusting ballast or shifting cargoes.
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Masayoshi KUBO, Kenji ASAKI, Yoshio NISHINO, Yasuo MAEDA
Article type: Article
1999 Volume 101 Pages
227-234
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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When a vessel runs aground or is involved in a collision. And oil spills inflicts significant damage to the surrounding sea and coastal area. To cope with such accidents, oil boom and oil tanker's double hull structure have been employed the performance and coast of the existing systems, however, are unsatisfactory, A more efective and more reliable system is thus desired. Under these circumstances, we propose "the Oil Curtain System" in which the vessel's circumference is encircled with a membrane to prevent spilled oil from dispersing. Basic research has been already performd on the theoretical and functional effectiveness of the system. In this study, the selection of the materials and the basic structure of the oil curtain are examined with the aim that this oil curtain system be put to practical use. First of all, we conclude that an impermeable membrane employing Polyethylene or Urethane is the most appropriate material for the curtain. Secondly, as a folding system, it is clarified that the bellows type is superior to the roll type or an extension and recovery system. The rope connected to the anchor weight opens the cover of the folded curtain automatically, enabling the curtain to be extended in a short time.
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Tsuneo ITAGAKI, Masaki MURAYAMA
Article type: Article
1999 Volume 101 Pages
235-242
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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Evacuation trial on domestic ro-ro passenger ship is reported to confirm the effectiveness of the evacuation chute system. The total of 356 passengers are participated in this trial and 244 passengers descended a vertical chute and transferred to five inflatable liferafts for 50 persons. Movements of all passengers and the various evacuating operations were recorded by video-cameras and bar-code readers. The time required for descending of 50 persons is analyzed, and total evacuation time is presented to be within one hour, when intervals of descending the chute between passengers are controlled in five seconds on average. An evaluation of the chute system is discussed through the measurements and observations in this trial from the points of ease and speed for each evacuating operations.
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Hiroaki KOBAYASHI, Shin MURATA
Article type: Article
1999 Volume 101 Pages
243-251
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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Recently, the ship handling simulator has been introduced into various marine technical training for improvement of each techniques. The training effectiveness using ship maneuvering simulator was already certified, however, there are few reports about quantitative comparison of the training efficiency between the onboard training and simulator training. In this paper, authors analyzed the characteristic of learning process of ship handling techniques by experiments for comparison of the training efficiency between the training ship and ship maneuvering simulator. As the result, it was clarified that there is the disparity of training efficiency based on the concept of elemental technique and compound ability between the both training methods. Consequently, it was confirmed that the higher training efficiency is obtained by the compound training using the training ship and ship maneuvering simulator.
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Shuji HISAMUNE
Article type: Article
1999 Volume 101 Pages
253-258
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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In Japan, the occurrence rate of the work accidents in the fishery industry is 8 times as high as that for all industries, so that it is necessary to study the factors relating to the works accidents in the fishery. In this study, I researched the movements of the workers on board trawl fishery, and studied the risk factors of the movements from the ergonomic point of view. I analyzed the movements, positions, traffic lines and postures of fishery workers on board the trawlers, and found out the work movements which involved different cycle times and various risks. The undesirable postures like deep bending and frequently squatting with heavy things and so forth, were always observed while at work. I extracted the most important risk factors, so that I made an operation manual to make fishing work safety. It is useful to take these factors into account in improving the work manual shout pay due these risk factors. The work manual was due to be distributed by The association for promoting safety and sanitation for seafarers to fishery companies all over the country.
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Hisayuki KUROKAWA, Saburo TSURUTA, Kunihiko SHIMA
Article type: Article
1999 Volume 101 Pages
259-269
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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As for the marine container transportation, remarkable development such as a harbor is done. The growth of the Asian area is especially remarkable. To cope with this growth, the size of the container ship becomes large, and then a transportation network changes into Hub-Spokes type and so on. This paper proposes the design method of the marine container transportation network. Then, plying of the vessel, the number of vessels, and so on are optimized by this design. The proposal method gives it the solution of a network problem as a minimum cost problem by using mathematical programming. The validity of this design method is shown in this paper. Therefore, a design example targeting the Asian area is presented.
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Masayoshi KUBO, Esther RODRIGUEZ SILVA, Hisanori NAKA
Article type: Article
1999 Volume 101 Pages
271-280
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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Masayoshi SOGA
Article type: Article
1999 Volume 101 Pages
281-289
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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Recently there is an important trial to increase the economical potential especially in North America and EU with international cooperation. In Far Eastern area there are some opinions that it is essential for Far Eastern economy to establish the first economic free zone including China, Korea and Japan, too. So in this paper the economical evaluation is tried for the efficiency that will be enhanced by Japanese-Korean Tie-up Option on the petroleum industry as a first step. The petroleum refinery and transportation system model is developed with linear programming method. Using this model, it is discovered that some Japanese-Korean Tie-up Option will be able to get higher efficiency economically equivalent for 300〜400 million US$ a year compared with non-Tie-up condition. For this improved condition, the quantity of petroleum transportation will have to be increased to 30〜38 million KL between Japanese and Korean, too. This amount is 2.7〜3.5 times as large as the amount in 1997. So it should be understood very well that the good availability of tankers for this transportation in this area would be necessary for the efficient economic condition in future.
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Katsuhiko SAITO, Masayoshi KUBO
Article type: Article
1999 Volume 101 Pages
291-296
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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Heavy shock acceleration occurs when the parcels are loaded by men. We carried out the laboratory experiments of loading work in a distribution center. The obtained results are summarized as follows. (1) Vertical shocks are bigger than horizontal shocks. (2) The principal direction of the horizontal shock is parallel to the back wall of a roll box pallet. (3) The parcel receives strong shock when it is put into far position in a pallet from the loading operator. (4) The shock absorbing materials should be laid on steel bottom of a pallet. (5) The loading operators should understand the relation between the shock acceleration and the loading work by some educational loading tests.
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Hiromune NAMIE, Akio YASUDA
Article type: Article
1999 Volume 101 Pages
297-305
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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GLONASS, being operated by Russian Space Agency, is a world wide satellite navigation system similar to GPS of US. Although the satellite number of the system has been reduced to 15 from the FOC of 24 satellites, as the SA of GPS is not introduced, the positioning accuracy is better than that of GPS during the period of a small DOP value. The use of both GPS and GLONASS together increases the number of usable satellites and improves the accuracy and availability especially while driving in the urban canyon. The authors tried the GLONASS and GPS+ GLONASS positioning while driving car and navigating ship. The accuracy is evaluated against the DGPS with MF marine radio beacon correction data dissemination. It is confirmed that the higher accuracy is available in the positioning by GLONASS with small DOP value and GPS+ GLONASS with more than 3 GLONASS satellites than that by GPS alone.
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Norio YUDA
Article type: Article
1999 Volume 101 Pages
307-315
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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Recent years, We have a great deal of ships that is fitted VecTwin Rudder. VecTwin Rudder is provided by two rudders that can rotate in a 360-degree arc. The Rudder has eleven typical movements, 'Ahead, Hovering, Astern, Turn to Starboard or Port, Astern to Starboard or Port, Rotate to Starboard or Port, and Stern to Starboard or Port'. The movements can be done by keeping propeller rotating ahead. The Rudder is very convenient system for use, but the relation between the movements and a position of a ship's helm has not been known in full. The hydrodynamic forces acting on the rudder are important to be understood in order to navigate VecTwin Ship safely. This paper tried to calculate to find the hydrodynamic forces acting in potential flow or vortex shedding flow.
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Hiroaki KOBAYASHI, Ichiro ONO
Article type: Article
1999 Volume 101 Pages
317-325
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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Maneuvering of berthing is one of the most difficult maneuverings situation which require ship handlers the specific knowledge and skill. A harbor pilot has to handle 5 tugboats effectively for maintaining her speed, course and position on his plan. However he makes wrong orders to the tugboat at specific situation, because of the human characteristics for the information processing. We carried out a research on the wrong usages of tugboats for berthing from viewpoints of human characteristics. As the results of studies, the following characteristics are obtained ; 1. When complicated ship's motion are required, the rate of making wrong operation increases. 2. When athwartships deviating from the object course lines enlarges, the rate of making wrong operation increases. 3. When number of tugboats to be handled increases, the rate of making wrong operation increases. 4. In case of highly frequent usages of tugboats being needed, the rate of making wrong operation increases.
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Shuji HISAMUNE, Kazuhiko KATO
Article type: Article
1999 Volume 101 Pages
327-334
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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The occurrence rate of the fishery worker's accidents becomes 8 times as many as that of all industry's worker's accidents in Japan. But, the scientific studies are not enough about fishery worker's accidents. So we studied the surrounding net fishery that is one of the most occurrences of accidents in fishing industries. In this study, we analyzed the movements of the worker in the surrounding net fishing boat, and studied for the safety of the worker from the point of the ergonomical approach. And will make the procedure book to reduce the dangerous work. We recorded fishery work by the VTR, and analyzed movements of fishery workers, as a result there was a difference of cycle time to each factors of the work, and this study was able to extract the dangerous factors from the point of the ergonomical approach. We will apply this method to other fishery and cargo ships.
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Article type: Appendix
1999 Volume 101 Pages
App3-
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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Article type: Appendix
1999 Volume 101 Pages
App4-
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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Article type: Appendix
1999 Volume 101 Pages
App5-
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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Article type: Appendix
1999 Volume 101 Pages
App6-
Published: September 25, 1999
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Article type: Cover
1999 Volume 101 Pages
Cover2-
Published: September 25, 1999
Released on J-STAGE: January 15, 2017
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