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Article type: Cover
1984 Volume 71 Pages
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Published: September 25, 1984
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Article type: Cover
1984 Volume 71 Pages
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Published: September 25, 1984
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Tsuneo SUZUKI, Haruo SATO, Ikuo OKUDA, Yuzo IGETA
Article type: Article
1984 Volume 71 Pages
1-9
Published: September 25, 1984
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The authors have made an experiment at sea in order to determine drifting characteristics of inflatable life-raft (home made the second type) and floating life-sized doll of a vertical style. Followings are summary of this experiment. (1) The drifting speed of the life-raft due to effects of wind and wave is roughly expressed as follows. Condition 1. V=0.113W Condition 2. 0.054W<V<0.101W Condition 3. V=0.084W Where V is the drifting speed in Knot, W is wind speed in m/sec at 10 meter above sea surface. Condition 1; an unoccupied deployed drogue and canopy, Condition 2; an unoccupied ployed drogue and canopy, Condition 3; an occupied half or full load ployed drogue and canopy. Direction of drift was the about leeward from the point where the life-raft brought by the current. (2) The floating life-sized doll was mainly transported by the current. The drifting speed by wind and wave was shown as follow. V=0.01W+0.061 (3) Based on this experiment, accurate estimation of the current appears to be the most important factor in searching a target (especially human body). From this point of view, detailed study of interaction between direction of ocean current and dislocation of floating material will be required in future.
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Kaname SATO, Tadashi TAKAHASHI, Hayao AKIZAWA, Yujiro SAOTOME, Kiyoshi ...
Article type: Article
1984 Volume 71 Pages
11-21
Published: September 25, 1984
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Keiichi KARASUNO, Shigeo KAWASHIMA, Katsuo YUI
Article type: Article
1984 Volume 71 Pages
23-28
Published: September 25, 1984
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This paper describes the test results of on-line and real-time analysis of maneuvering motion of a fishing boat by a digital autopilot. The analysis due to model reference adaptive system (MRAS) method, which is implemented in the digital autopilot, is compared with those due to linear equation method (L.E.M.) and least square method (L.S.M.) which are usually used. Conclusions are: 1) The Nomoto's steering qualities indices T and K obtained by MRAS, are much coincident with those obtained by L.S.M. for 5deg. or 10deg. zig-zag maneuvering tests. 2) Ship maneuvering motion of 5deg. zig-zag test are simulated with respect to T and K estimated by analysis methods, and they are found to be similar to each others, in spite of differences in T and K according to analysis methods.
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Hideo YABUKI, Toshio IIDA, Haruo KUSAKA
Article type: Article
1984 Volume 71 Pages
29-36
Published: September 25, 1984
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It is indicated that the Crash Astern Stop Performance of the ship equipped with Hiqhly Skewed Propeller (HSP) is inferior to that of the ship with Coventional Propeller (CP) by means of the theoretical simulation. However, few works have been carried out by means of full scale measurements. We fitted out Training Ship Seiun Maru (5061.17 G.T., Diesel Engine x 1) with 45°HSP and compared the Crash Astern Stop Performance of 45°HSP with that of CP. From the results of the full scale experiments, the following conclusions were obtained. (1). The power of HSP at astern condition is inferior to that of CP. (2). In the case of reverse her engine from sea speed, stopping time of the ship with HSP is longer than the time of the ship with CP but stopping distance are nearly the same. (3). In the case of reverse her engine from manoeuvering speed, stopping time and distance of the ship with HSP are relatively longer than those of the ship with CP.
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Tamaki URA
Article type: Article
1984 Volume 71 Pages
37-45
Published: September 25, 1984
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Full scale trials on three types of anchor were carried out in the sand bed off Matsuho-no-Ura, Hyogo Prefecture. Newly designed absolutely-roll-stable single fluke anchors (ARS-S Anchors: 6, 3, 1ton) proved to be very active and developed the holding power approximately 6 times the weight of anchor. The maximum holding power ratio of stockless bower anchor (Hall's Anchor: 5.6ton) was about 3.5. It should be noted that Hall's Anchor turned over in all trials. It was observed that the fluke often failed to penetrate the sea bed. Stocked Anchor (5.2ton) was stable but developed poor maximum holding power ratio about 3.6. The maximum holding power of anchor depends on the deformations property of the sea bed soil. There are, however, few informations about those of the anchorage. Under existing circumstances, it is not easy for an anchored ship to estimate the capacity of mooring force in order to prevent anchors from dragging. In this paper, the philosophy and the procedure of measurement are discussed for the inspection of the geological characteristics of the sea bed. The concept of "standard inspection anchor" is introduced so as to get the index of the sea bed soil for the advantage of anchoring. With the aid of "standard inspection anchor", it will be possible to fulfil the map of holding power index of sea bed soil over the anchorage.
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Arao KOYAMA, Saburo TSURUTA
Article type: Article
1984 Volume 71 Pages
47-54
Published: September 25, 1984
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In the present report we have studied the method of improving the holding ability of anchor. We mainly pay attention to three characteristics of anchor, that are tripping ability, stability and holding power. The results may be summarized as follows. * In the condition that anchor is laid on ground, to leave gap between ground and the anchor except tripping part and bills improves tripping ability. * To minimize the width of tripping part improves stability and holding power. * To attatch wings like wedge to the shoulder improves stability remarkably. Using these results we have produced trial model anchor. And we have ascertained the excellent performance of the new type anchor.
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Yoshiro IMAEDA, Sukita NAKAHARA, Ryuichi KIMURA, Masayoshi KUBO, Tateh ...
Article type: Article
1984 Volume 71 Pages
55-61
Published: September 25, 1984
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Postural responses of subjects who feel dizzy on a rotating table were observed. The sways of the head and of the body center of gravity were rocorded and analyzed by means of their frequency power spectra and their Lissajous's figures. When the rotating direction of the table is reversed, the rotating direction of the body center of gravity of a subject on the table is very likey to be also reversed. As the subject sways standing with eyes open, the center of sway shifts leftward (rightward) with the table rotated clockwise (counter-clockwise), although the center of sway of the subject standing with eyes closed indicates no shift. As the angular velocity of the rotating table is increased, durations of nystagmus and dizziness of the subject get longer. The analysis of power spectra and the Lissajous's figures for the various foot positions shows that power spectra for the Mann's posture, indicating greater instability, was composed much of higher frequency.
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Nobuo KIMURA, Rihei KAWASHIMA
Article type: Article
1984 Volume 71 Pages
63-70
Published: September 25, 1984
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The authors have previously reported on the human responses to a ship's motions. In this paper, the authors performed the experiments using actual ships, and made the following analyses: (1) Estimation of human frequency responses functions to a ship's motions. (2) The distribution of the gravity of the human body on the deck measured by the use of FORCE-PLATE. (3) Relationships between the acceleration boundary of the human body and the severe discomfort boundaries for ultra low frequencies (ISO proposal 1975).
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Shunji JANUMA, Rihei KAWASHIMA
Article type: Article
1984 Volume 71 Pages
71-76
Published: September 25, 1984
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Since the righting quality of a ship is closely related to the ships motions, it is necessary to discuss this relationship. For this purpose, the authors used the phase space-which is composed of rolling angle, rolling angular velocity and rolling energy axis-to analyse and discuss the righting quality of the ship, based on motion records obtained by an experiment with a model fishing boat in wind waves.
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Nobuo KIRIYA
Article type: Article
1984 Volume 71 Pages
77-82
Published: September 25, 1984
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In order to clarify the cause of men fallng overboard, some situational factors were analysed by the mathematical quantification theory type III. About 135 cases which were sampled from the records of the marine courts, the author has investigated the actual condition of the accident. And these samples are classified 8 items. The characteristics of accident patterns were represented by using the type III. From this study, it became clear that these patterns are decided by the agency, the source of injury and specific factors.
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Yasutake NISHIYAMA, Taketoshi YAMADA, Hisashi MATSUMURA
Article type: Article
1984 Volume 71 Pages
83-92
Published: September 25, 1984
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The second revision of the International Convention for Safe Containers (CSC) was adopted at the Maritime Safety Committee of the IMO in 1983, and came into effect at January, 1984. This Convention was ratified already by the Japanese Government, and domestic regulations concerned were also enacted. Under the CSC, all the distributing containers have to be inspected and maintained periodically and have to put CSC Safety Approval Plate on for the proof of sound container. The purpose of this simulation study is to estimate the sensitivity of the maintenance shop function and the impacts on the efficiency of the container terminal operation and container distribution under the CSC. The results of study are as follows: (1) The strategical variables influencing on the sensitivity of maintenance shop function are the damage rate, the number of containers handled, the repair time and the number of repair team in order of influence size. (2) The works of CSC inspection and maintenance should not be start without improvement of existing condition of variables. (3) The works of CSC inspection and maintenance can be carried out with one and half times of the existing repair team. (4) The repair team reinforced by two times of the existing can cope with the works of CSC under the bad conditions-complex. (5) Sufficient capacity for the legal periodical inspection is two channels. (6) Under the prediction of increasing the number of containers and damage rate, safe handling in the terminal and control of damage occurrence through the risk management should be carried out.
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Taketoshi YAMADA, Takayuki KUROSHIMA, Tadashi TANAKA
Article type: Article
1984 Volume 71 Pages
93-101
Published: September 25, 1984
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The purposes of this study are to build the good computer model of CFS function making use of actual cargo data on the CY and CFS, and also to calculate the cargo inventory volume through the model. The validity of this CFS model is considerably high and the outputs of parametric case studies are also reliable. The output distribution of inventory volume from this model could be used for the decision making of the optimal CFS capacity through the tradeoff analysis. And it is also confirmed that the double queueing theory should be applied strictly only when the distributions of the cargo arrival and departure are both equal to the Poisson distribution. This model could be also applied to planning of general warehouse by changing the input package of data distribution.
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Yoshimi NAGAO, Katsuhiko KURODA, Kinzo INOUE
Article type: Article
1984 Volume 71 Pages
103-114
Published: September 25, 1984
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Two models are proposed for evaluating the safety level of a ship moored at a berth inside a harbour under stormy weather such as typhoon. One is based on the first passage problem of a stochastic process, and the other is based on the extremal probability distribution. Both methods can evaluate a probability that the random tensional response of a mooring rope to random external forces by wave, wind and high-tide exceeds its strength. According to the computational results of both methods, followings are concluded; (1) The first passage failure model should be used when the average value of the induced rope tension is 40% or more of the rope strength. (2) The extremal probability model has no practical difficulty in case that the average value of the induced rope tension is under 40% of the rope strength. Proposed models give us many information regarding with the safety level of the mooring system. Therefore they are useful for decision making on the engineering planning and design of the mooring system under stormy weather.
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Hideo OGURO
Article type: Article
1984 Volume 71 Pages
115-122
Published: September 25, 1984
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This report is described on oil diffusion at restricted water area by ships which have come into collision or stranding. The experiments were carried out using 2.5m×2.5m×0.35m water tank, small ship models and turbine oil. The water surfaces were at still and flowing condition. The diffusion areas were measured by picture analyzer from photograph. The results of experiments were as follows; (1) In the case of succesive flow of oil, the diffusion area can be calculated by formula (2), after a certain elapsed time. On this experiments, the velocity gradient coefficient C of formula (2) are 1.0 and 0.3 at still and flowing condition. (2) The calculated diffusion areas by the finite element method agreed to adopted mean oil thickness of diffusion area at our experiments.
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Hayama IMAZU, Takeo KOYAMA
Article type: Article
1984 Volume 71 Pages
123-130
Published: September 25, 1984
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The subject of this study is to make an optimum criterion for collision avoidance action deciding by navigator. This criterion can be used for training of collision avoidance and design of a collision avoidance aids. Here, three kinds of decision-making model which considered about a collision risk by multi-targets and an action loss by a deviation of ship's position and by an action change, were made. Then, these models were evaluated by simulation method. The results by the simulation tests showed that it was better for reducing the action loss to have actions of every sort, and it was necessary to consider about a change of targets distribution at decision of own ship's action.
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Saburo YAMAMURA
Article type: Article
1984 Volume 71 Pages
131-137
Published: September 25, 1984
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This paper presents a framework for measurement of discrimination on navigation light marks at night. It is assumed in this model that a degree of discrimination of a pair of two navigation marks is affected by three kind of attributes: the intensity of illumination, the light patterns and the angle between the marks. It is sufficient to identify at least three navigation marks in order to estimate an observer's position without side information. Therefore, the second largest degree of discrimination among all the pairs of marks is a dominant factor. The measurement is available for the evaluation of planning of navigation marks, maneuvering environment and so on.
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Nobumichi ISHIMURA, Takeshi HASHIMOTO
Article type: Article
1984 Volume 71 Pages
139-146
Published: September 25, 1984
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Of primary importance in the use of digital maps is to find an effective data compression method that permits the data to be stored compactly and reproduced easily beause digital maps normaly consist of a large amount of data. In this paper, a new method is proposed for data compression of coastline data in digital maps based on the best approximation to cubic spline functions with their knot positions optimized relative to the approximation errors by using a modified dynamic programming. This method based on the modified dynamic programming can shorten the CPU time to calculate the approximation functions in comparison with one based on the ordinary dynamic programming without substantially increasing the approximation errors.
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Sakae NAGAOKA
Article type: Article
1984 Volume 71 Pages
147-157
Published: September 25, 1984
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Data on height keeping errors of approximately twenty thousands aircraft flying at or above flight level 200 (20,000 feet) have been collected using the specially designed height finding radar (NAMS: Navigation Accuracy Measurement System) installed under a trunk airway (at Sendai Airport). The data are analysed for the purpose of studying the distribution of relative vertical distances (RVD) of aircraft pairs in order to estimate the probability of vertical overlap of an aircraft pair. This paper describes the observed distribution of the RVD (which is defined as the difference of two measured heights of a pair of aircraft) obtained by observation of cruising height of aircraft passing over the NAMS site. A parameterization based on the maximum likelihood estimation for the distribution of RVD of aircraft is made assuming that the probability density function (pdf) of the height keeping error, f(x) is the double exponential distribution, i.e., f(x)=(2λ)^<-1>exp(-|x|/λ) where λ is a scale parameter. Two models of pdf of RVD based on this distribution are applied for this parameterization. Results indicate that the model in which the effects of measurement errors are taken into account fits fairly well to the empirical distribution. In addition to this several statistical characteristics of distributions of RVD data are discussed in this paper.
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Saburo YANAGAWA, Toshiharu KAKIHARA
Article type: Article
1984 Volume 71 Pages
159-166
Published: September 25, 1984
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For the purpose of studying the characteristics of a pole and line fishing boat by group operation and the situation of collision avoidance of navigating ships for group operating fishing boats, the authors carried out marine traffic survey by both a visual and a radar from the sixth to the seventh of August, 1981, off Hino Misaki. In this paper, are described the presence of the effective domain, arround a fishing boat in operation, into which other fishing boat avoid entering and the difference between navigating ships and fishing boats relating to the sense of safety distance.
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Minoru HIROTA, Shigetaka NAGANO
Article type: Article
1984 Volume 71 Pages
167-176
Published: September 25, 1984
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In planning a sailing schedule to minimize fuel consumption of a ship, we must estimate currents, the effects of fouling, winds and waves. One of the good ways for this purpose is to analyse the abstract logbook of a ship running the same route many times. Ship speed over ground V_0 is affected by many factors. We assume the following equation concerning to the mean value of a one-way voyage. V_0=V±S+C(d-d^^^)+D(h-h^^^) S=S^^^+Asinωt+Bcosωt where V: ship speed through water, S^^^: yearly mean of ocean current, A, B: amplitudes of seasonal change of the current, C: coef. for fouling, D: coef. for winds and waves, t: days after beginning of a year, d: days after docking, h: hours when strong winds (Beaufort scale above 6) are blowing, + sign for homeward, - sign for outward voyage. Abstract logbooks from three tankers sailing between Japan-Persian Gulf are analysed. Then, A: negligible, B≒-0.3' fouling effect is 0.4'〜1.3' speed down per year, and strong wind effect is 1.3'〜2.2' speed down. The anual mean S^^^≒0.1' is estimated from current chart. The root mean square of residuals of experimental equations are reduced to half when these values are applied to the fuel consumption F=KV^a△^b.
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Article type: Appendix
1984 Volume 71 Pages
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Published: September 25, 1984
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Article type: Appendix
1984 Volume 71 Pages
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Published: September 25, 1984
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Article type: Appendix
1984 Volume 71 Pages
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Published: September 25, 1984
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Article type: Appendix
1984 Volume 71 Pages
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Published: September 25, 1984
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Article type: Appendix
1984 Volume 71 Pages
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Article type: Cover
1984 Volume 71 Pages
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Published: September 25, 1984
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Article type: Cover
1984 Volume 71 Pages
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