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Article type: Cover
1974 Volume 52 Pages
Cover1-
Published: December 25, 1974
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Article type: Cover
1974 Volume 52 Pages
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Published: December 25, 1974
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Kiyoshi HARA
Article type: Article
1974 Volume 52 Pages
1-7
Published: December 25, 1974
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Author proposed a model for estimating the trip distribution between each pair of centroids such as harbours and straits. The model was mainly based on the concept of entropy and the trip distribution was derived only from traffic volume through harbours and straits. The model was numerically applied to ships on marine traffic routes in Osaka Bay in order to study model feasibility. The trip distributions in Osaka Bay for various sizes of ships by the model was compared with those observed by a large scale traffic survey there and their agreements were found to be good except for the ship size larger than 3, 000T. The reasons why trips at sea can be expressed by the simpler model than that at roads seems to be due to the simplicity of traffic routes and objects and no alternative means of transport but ship. It would be capable by the model for us to evaluate such problems as the encounter rate of the crossing in a bay and the contribution of increase of traffic volume at one harbour to the other.
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Akio M. SUGISAKI, Hiroshi KIKUTANI, Susumu KAWAJIMA, Kohei OHTSU
Article type: Article
1974 Volume 52 Pages
9-15
Published: December 25, 1974
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In the straight channel approaching to port, ships decrease their speeds in order to enter the port. The reduction of set speed is standardized in proportion to ship's length and distance to port. As the results of simulation using above relation, the traffic capacity is about 40 ships per hour and the mean speed at entrance of port is 40% to the original full speed. This capacity is about one-third to that of straight ehannel to open sea. The simulations were performed in the next conditions as follow ; the channel width is 700 meters, and ship's size is distributed to the mix mode which is equivalent to the ship of 73 meters in length.
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Akio M. SUGISAKI, Hiroshi KIKUTANI, Susumu KUWAJIMA, Kohei OHTSU
Article type: Article
1974 Volume 52 Pages
17-22
Published: December 25, 1974
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In the 4-th series paper, Authors tried to estimate a practical traffic capacity of merge type channel system in which a sub channel having about 8 nautical miles in total distance and 700 meters in width, joined a main channel having about 13 nautical miles in total distance and 700 meters in width at an angle of 45 degrees, forming an inverted shape of the letter. The method to manouvre a ship in the straight parts of this channel was followed basicly the former method which had written in previaus three papers, while in the joining parts and it's neighbourhood, we adopted such a manouvring method as two or more ships could not previously approach each other as much as possible to avoid the danger of collision at enough distance. According to the computing result, for example, the capacity of this channel system was estimated to be 38.5 ships per one hour in the sub channel at 15 ships per one hour in the main channel, when all ships had 73 meters length of standard ship type in 1985.
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Yozi AMEMIYA
Article type: Article
1974 Volume 52 Pages
23-29
Published: December 25, 1974
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This paper consists of the following chapters 1. Preface 2. Notion of technics of ship's operation. 3. Aufheben of Mercantile marine technology ; change to Engineering science. 4. Capitalistic application of the technology and the influence on seamen's labor (1) The logic of technical inovation of ship's operation. (2) Contradiction in capitalistic application and seamen's labor. 5. Conclusion It is an important point of view for the technological deveopment of ship's operation that seamen's labor is getting close to engineering scientific work.
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Tsukasa NAGAHATA
Article type: Article
1974 Volume 52 Pages
31-36
Published: December 25, 1974
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The basic reseach about the characteristic of navigators is the field which is the most tardy and is yet unsolved. The purpose of this paper is to investigate in more detail the characteristic of navigators on the maneuvers for avoiding collision which has been mentioned in the previous paper. It became clear by analysis of investigating the actual condition in the radar filmes, that the threshold value on the fear of navigators about collision was satisfactory agreement with the theoretical curve under several assumptions. In this type of investigation, the choice of the method is in itself a difficult problem, but it was to find a certain relation between V_θ and ΔL, where V_θ and ΔL are respectively linear velocity and evading distance.
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Kiyoshi HARA, Kinzo INOUE
Article type: Article
1974 Volume 52 Pages
37-42
Published: December 25, 1974
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Authors proposed a method for measuring the maneuvering elements of a ship at handlings for berthing or clearing a berth by means of a video system equiped on shore. The trajectory, velocity vector and heading angle of a ship under way were derived from the two kinds of data, one the vertical and horizontal lengths of parts of a ship on TV picture recorded by a video tape recorder, the other the precise direction of TV camera. The measured values of the elements by VTR system at the actual maneuvers were compared with those by such nautical instruments as radar, log and gyro compass, and their agreements were found practically to be good.
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Yurin SAKAMOTO
Article type: Article
1974 Volume 52 Pages
43-48
Published: December 25, 1974
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A ship's motions (surging, heaving, swaying, pitching, rolling, yawing) and her fuel consumption were measured while sailing on her 12 different courses in the same maritime and meteorological conditions. The author made an analysis and has got the following results: Based on the data of the ship's motios measured, some power spectra and the variances of the amplitude of motions were obtained ; those results are illustrated in Fig.2-7 (using circle graphs). As an index value of the ship's motion, an integrated value of modified power spectra was used, and the correlation matrix between fuel consumption and index values of the ship's motions are shown in Table 2. Fig.8 shows the relation between fuel consumption and the ship's courses. The relation between fuel consumption and the index values of surging, heaving and pitching are shown in Fig.9-11. The correlation between fuel consumption and surging is stronger than that of fuel consumption and the other factors.
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Kohei OHTSU, Michio HORIGOME
Article type: Article
1974 Volume 52 Pages
49-56
Published: December 25, 1974
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The efficient identification method of dynamic system having a feedback loop has not been developed in the modern control theory. However to this problem, as far as the feedback system had the stationariy auto regrssive type structure in time domain, Dr. Akaike succeeded to statistically estimate these system dynamics in his later papers. Authors tried to apply this Akaike's method to the identification of ship's dynamics in yawing motion, In this short paper, we examined about these results from various view points.
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Hisashi KUGUMIYA, Yoichi MOROOKA, Nobumochi SHIOTA, Yasuhiro NAKAMURA
Article type: Article
1974 Volume 52 Pages
57-64
Published: December 25, 1974
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Suppose that a ship is advancing on a straight pass with a constant speed, when her rudder is deflected and held at a fixed angle. The pivot-point appears and moves generally as follows, (1) the pivot-point appears at the centre of percussion, which is the dynamical point when a blow is given to the position of rudder, and (2) with the growth of her turning, the point moves to forward, and (3) when her turning reaches to steady state, the point settles down at ca. Lpp/3 from midship. There is no definite theory, however, on the location of the point when a ship goes astern. Authors tried to find out the point by experiments using two ships, and concluded that the pivot-point exists afterpart of the ship at least when the astern turning reaches to steady state.
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Shihei NOMURA, Hiroshi KIKUTANI
Article type: Article
1974 Volume 52 Pages
65-74
Published: December 25, 1974
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In this paper the results of pulling tests in wet sand for anchor models are given. Two anchor models with different fluke length are tested varying in fluke angle. The effect of fluke length and angle on the holding capacity is investigated and the results are compared with the calculated values given in the former report. The measured results show good agreement with calculated ones.
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Tomomi WAKAO, Koichi KUWAZAKI, Jyoji INAGAKI
Article type: Article
1974 Volume 52 Pages
75-80
Published: December 25, 1974
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The intensity of light which the navigators actually feel from the background light differs depending on the brightness of the light source, as well as on the length of the background light spreading in the shape of a belt on the horizon, and it is also considered to vary with the direction of visual line of the navigators trying to find the navigatianal aids or signals, etc. For such reason, indoor experiments were conducted concerning the sensitivity distribution in the horizontal direction of eyes for the light, and based upon their results, a study was made about the relation with the 20°visual field. As a consequence, the measuring value by means of a drightness meter of 20°visual field, which was obtained hitherto as a relative value, could grasp quantitatively the sensitivity distribution of eyes, so that it has become possible to convert it into the absolute value. Furthermore, as a result of having grasped quantitatively also about the effect of lamplights around the visual field, we could find there exists something that cannot be ignored from the view point of navigation safety.
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Akira M. SINZI, Akio SENDA
Article type: Article
1974 Volume 52 Pages
81-86
Published: December 25, 1974
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Calculation formulae of E (or GHA) and d of celestial bodies suitable for small computers on board were investigated. The following expressions were found to be the simplest: For the sun: Combination of a polynomial and Fourier series, For planets: Fourier series, without synodic periods, For stars: Approximation of the Bessel-Suzuki formula ; merely the principal term (moon's node, 18.6 yrs.) is adopted for nutation, and the earth's orbital velocity is substituted by the sun's mean anomaly to calculate aberration. Mean errors of the empirical formulae for the sun and planets are within ±0^s.3 in E and ±0'.04 in d. By the approximation formulae for stars, errors are within ±0^s.1 in E (except for Polaris) and ±0'.01 in d
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Hayama IMAZU
Article type: Article
1974 Volume 52 Pages
87-93
Published: December 25, 1974
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This report is a description of a method of solution for obtaining ship's sailing parameters (latitude, longitude, speed, course) and sky wave correction from Loran data. It consist of applying successive differential corrections, obtained by a least squares treatment, to a set of initial approximations for the ship's sailing parameters and sky wave correction. Chapter 4 presents the results when the method of solution was applied to Loran measurements of T.U.M.M. Training Ship Shioji Maru on 23rd of July 1974. The parameters, which were determined, agree very well with those published by cross bearings and radar. The computed height of reflection of wave of frequency 100kHz, have been obtained with this experiment, was about 66.5km and the angle of incidence was about 81.5 degree.
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Sinichiro KAWAGUCHI, Masami ISHIDA
Article type: Article
1974 Volume 52 Pages
95-100
Published: December 25, 1974
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The auther describes a study of the dynamical properties of decometer readings for Decca System in the night. The experiments were performed from JUL.1972 to JUN.1973, every 2 minutes observations. (1630-0730) In this study, it is considered that decometer readings are the output of this System. For analysing the date, the statistical analysis was applied. The following results were obtained and discussed: 1) The distribution of the amplitude of decometer readings were shown to de Gaussian. 2) Standard deviation of winter was the maximum value compared with other season. 3) Concerning the power spectrum calculated for the above data, it is found that the Random error for Decca System consists of much low frequency componentesand a few high frequency components. The computations for the statisyical analysis were performed at the computer center of Hokkaido University.
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Tomiji NIRASAWA, Hiroshi OKADA
Article type: Article
1974 Volume 52 Pages
101-108
Published: December 25, 1974
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An automated s.t.c. system for marine radar is presented. In this system, sea-clutter whose strength depends upon the wind-direction is effectively suppressed by using the feed-back loop. This system is a kind of c.f.a.r. (constant false alarm rate) receiver, and applicable to the radar set which has the conventional s.t.c. circuit.
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Kazuo TAGUCHI
Article type: Article
1974 Volume 52 Pages
109-115
Published: December 25, 1974
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OMEGA propagation disturbances have been studied by the author and he presented the two papers already, but the experimental results were reanalised by the solar terrestrial physical and geomagnetic data published later. Examining the results of twice trans-Pacific experiments made in 1969 and 1971, it was ascertainable that more significant features of OMEGA disturbances were found at high latitudes, and the phase fluctuations of sudden change were great and rapid. In this paper, however, the author publishes Magnetic anomalies and Aurora hiss. The magnetic storm occured along the propagation path of OMEGA signal gives rise to the propagation disturbances. The phenomena discussed here were shown in the following predominant pattern. Namely, fluctuation of OMEGA signal synchronized completely with the geomagnetic anomalies. In the precise description, when the magnetic variarion set in maximum, the phase disturbance was started, the phenomena during the anomalies were lasted, and it ceased when the variation recovered the original value. The duration was about 9 hours and the fluctuation was 20 cel in maximum. Additionally, aurora hiss was observed frequently around the Aleutian Islands. Through the experiments, the author would propose that simple field strength meter of signal was an useful detector for the solar terrestrial disturbances capable of avoiding the systematic error.
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Hideomi NASU, Koichi KIMURA
Article type: Article
1974 Volume 52 Pages
117-123
Published: December 25, 1974
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The optical path of radio wave propagation through the ionospheric layer is bent for the variation of refractive index in the layer. This phenomenon causes the error of the position fixing by a single channel navigation receiver in the Navy Navigation Satellite System (NNSS). This paper describes the estimate method of these positioning errors. If it is assumed that electron density of the ionospheric layer distributes uniformly from about 85km to 1, 000km over the earth, we can caluculate easily the apparent satellite position. Using this simple model of the ionospheric layer we computed errors due to ionospheric refraction at various total electron contents and counted amplitudes and directions of the position fixing errors by a single channel (400MHz) NNSS receiver without onospheric correction. These results was compared to practical positioning data. By these analyses it became clear that (1) the position fixing error due to ionospheric refraction was displayed to the west of the receiving station when the NNSS Satellite passed through on the east of the station, and to the east of the station when the NNSS Satellite passed through on the west of the station (2) its amount was about 1km in day time (total electron contents 5×10^<17> electron/m^2), about 0.2km in night (total electron contents 1×10^<17> electron/m^2) when the satellite taked peak elevations between 10° and 50° and rapidly increased when peak elevations were more than 80°.
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Shuji NISHI, Koichi KIMURA
Article type: Article
1974 Volume 52 Pages
125-131
Published: December 25, 1974
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Omega and Navy Navigation Satellite System have been increasing utility value in the elecronic sea navigation field. Both systems have global coverage but individual merit and demerit. The former has unrestricted user time while the latter has high position fix accuracy as merit. Contrary to this character, the former has low position fix accuracy while the latter has restricted user time as demerit. In order to correct these opposit demerits, we propose here Omega/NNSS hybrid navigation system with data processing by Kalman filtering in which Omega works as velocity sensor every two minutes. The paper describe construction of the hybrid navigation, calculation procedure of the position fix by Kalman filtering and simulation of the system assuming various noises. Results of Monte Carlo simulation showed that 50〜80% accuracy improving is feasible in proposed system compared with normal NNSS position fix method.
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Torao MOZAI, Kingi HIRAIDE
Article type: Article
1974 Volume 52 Pages
133-138
Published: December 25, 1974
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This equipment accurately measures the bearing and distance of a transponder immersed in the sea using gyrocompass, radar, and rudder angle signals for the measurement. Based on this, each maneuvering performance of ship is automatically recorded and because of high accuracy of performance measurement at the time of trial. This was an actual ship test performed on the Shioji-maru, ship of Tokyo Shosen University (Mercantile Marine University) at Tateyama of Tokyo Bay. This test mainly dealt with maneuvering test, turning trial, and measurable distance range test. Satisfactory results were obtained in the case of maneuvering test and turning trial, and the measurable distance test it was confirmed that the measurement is possible upto 16km.
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S. Nagasawa, H. Asano
Article type: Article
1974 Volume 52 Pages
139-142
Published: December 25, 1974
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What is required of seamen's ordinary skill and ordinary intelligence is not expected to foresee. It is a question of fact to be decided on a consideration of all the relevant circumstances. But I say, this is the attitude to guard against, to confirm, and to consider carefully for peril of the sea.
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Rihei KAWASHIMA, Yasuhito INABA, Kiyoshi AMAGAI, Susumu TAKAHASHI
Article type: Article
1974 Volume 52 Pages
143-148
Published: December 25, 1974
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These are experimental studies on the capsizing mechanism of a fishing doat due to wind waves on a heavy sea. The experiments were performed at the experimental areas A and B, in Fig.1, using a radio controlled 2-meter fishing boat model. The condition of the model in the experiment is shown in Table 1. In the experiment, when the wind velocity was 6m/sec and the maximum wave height was about 25cm, the capsizig of the model happened in the so-called following sea condition at area B, in Fig.1. The behavier of the capsizing model boat was observed and recorded by an 8-mm cine camera and the wave heights were observed simultanously by the use of a wave pole. According to those abservations, the authors discussed capsizing of a fishing boat in wind waves.
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Yahei FUJII
Article type: Article
1974 Volume 52 Pages
149-159
Published: December 25, 1974
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The result of studies on marine traffic flow and accident should be used for establishing proper navigation control. Quasi-quantitative analysis is made here to relate the degree of collision danger and the degree of control. The former one is assessed by "points" with respect to (1) ship size and number of persons on board, (2) waters (harbour, strait, etc.), (3) visual range, (4) diurnal traffic pattern, etc., where point "n" corresponds to multiplication with a factor of about 10^<n/2>. The latter, the degree of control, is evaluated roughly with its contribution to safety. Finally, the suitable degree of control is proposed, if we consider about safety, which is given by point of control=N+point of danger, where N is the point of safety standard and should be increased as years go by.
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Article type: Appendix
1974 Volume 52 Pages
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Published: December 25, 1974
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Article type: Appendix
1974 Volume 52 Pages
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Published: December 25, 1974
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Article type: Appendix
1974 Volume 52 Pages
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Article type: Cover
1974 Volume 52 Pages
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Article type: Cover
1974 Volume 52 Pages
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