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Article type: Cover
1988 Volume 78 Pages
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Published: March 25, 1988
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Article type: Cover
1988 Volume 78 Pages
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Published: March 25, 1988
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Kazuo TAGUCHI, Mitsuo SUENAGA, Michiko YAMASHITA
Article type: Article
1988 Volume 78 Pages
1-12
Published: March 25, 1988
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Observations of OMEGA Australia signal in the North Western Pacific and OMEGA Japan signal in Australia were performed. Unexpected number of cycle jumps occur in both OMEGA signals of 10.2 and 11.3kHz. Using the observation with ship over the North Pacific, it is found that the jump of OMEGA Australia of 10.2kHz first appeared in the longitude of 155°East and the number of jumps increased as we move to the west. Since this longitude of 155°East corresponds to magnetic north from OMEGA Australia, this phenomena will be caused by the magnetic azimuth and latitude dependence of OMEGA propagation. Moreover the same result is able to detected in Australian receiving sites as well. Through the experiment, 13.6kHz signals from both transmitters did not jump over almost area which suggests an availability of 13.6kHz for the navigational frequency instead of 10.2kHz.
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Kanemichi KASAHARA
Article type: Article
1988 Volume 78 Pages
13-22
Published: March 25, 1988
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Recently, some methods for direct finding a fix by two position circles were proposed and brought into use. These methods have significant advantages for eliminating errors inherent to the line of position. To apply these methods for non-simultaneous observation, the first position circle is needed to be transferred, but the current method of transfer has some defects which seem not to be negligible in the case of high altitude observation or long distance transfer. The author, hence, contrived a new method of transfer, by which exact solution can be got. That is: (1) Calculate the first estimated distance D_c between the center of first position circle and first D.R.P. (2) Transfer above mentioned two positions according to the distance-run. (3) Calculate the second estimated distance D'_c between above mentioned two transferred positions. (4) D'_o=D_o*D'_c/D_c: where D_o is observed radius. (5) The circle with the radius of D'_o at the center of transferred position circle is the transferred position circle.
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Susumu KUWASHIMA
Article type: Article
1988 Volume 78 Pages
23-33
Published: March 25, 1988
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The profile of encounter waves (which is measured by the ship under-way) is known to be different from that of original waves (which is measured by the stationary ship). That is why the frequency of each component waves are deformed in propotion to ship's speed and relative course to the wave direction. This means that the encounter waves contain the directional information of each component waves. So, author developed the analyzing method of encounter waves applying "distribution fitting method" to estimate the directional spectrum of original wave. And it was made clear that the directional spectrum is computed by this method with certainty and short time comparatively.
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Hirotsugu WAKE, Kiyoshi HARA
Article type: Article
1988 Volume 78 Pages
35-41
Published: March 25, 1988
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The construction of several long bridges over the Seto Inland Sea are in progress. Bridge lights are very important for safety vessel traffic. In this paper we investigated the effects of these lights on the statistical characteristics of ship's track distributions. The ship's tracks were observed by radar on two different light-conditions at Naruto Kaikyo. One was there was only one temporary light on the center of bridge. The other was there were both a center light and side lights on the bridge. The result are summarized as follows: (1) The basic navigational rule of keeping to the right becomes more clear by fitting the side lights on the bridge. (2) The standard deviation of ship's track distributions increases approximately proportionally to the square of the distance from the bridge. Although these results obtained for a bridge at the strait, it is conceivable that they are applicable to the same case of other bridges.
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Yasuyuki SHIRAI, Kiyotaka SAITO, Hiroshi SUZUKI
Article type: Article
1988 Volume 78 Pages
43-47
Published: March 25, 1988
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In order to obtain the information of ship's motion (rolling, pitching and yawing), there have been a lot of sensors such as gyro-compasses, vertical gyros, angular rate sensors and so on. Recently, studies on a rate sensor type gyro without mechanical rotors were advanced. This paper describes about the measurement of ship's motion using turning fork angular rate gyros. The authors obtained the following results. 1) Rate information of ship's motion was comparatively well obtained. 2) The DC power unit and output circuits become compact and the signal processor is easily available. 3) Compensation of the error due to temperature change and vibration is necessary.
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Tadashi NARITA
Article type: Article
1988 Volume 78 Pages
49-61
Published: March 25, 1988
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In this report the author continues to describe a theory of Strapped Down mechanizations of Free Surface inertial navigation. The paper deals with the theories of the types IN (RSD) and I (2 SD) mechanizations, and this completes a description of the main points of the whole theory of SD mechanization. As a supplementary item, a new method of calculating geographic coordinates is proposed for the types NS (SD) and I (1 SD) mechanizations. This new method is considered to be more orthodox than formerly derscribed trial method. The next step to this serial work, may, the author thinks, will be a theoretical comparison between the FS mechanizations and the ordinary mechanizations (e.g. north slaved local level), and those among the FS mechanizations. However, it is anticipated that these studies will take a lot of time and efforts, the author wishes to report the results of them some other day, if possible.
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Hiroaki KOBAYASHI, Kimiko NAKAGAWA
Article type: Article
1988 Volume 78 Pages
63-71
Published: March 25, 1988
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The study on the training process of the ship's operator shows the characteristics of the man-machine system, so, its results can be used to decide the requirement of the ship manoeuvarability and fairway condition. Authors studied the training process in the tracking task for 6 fairway conditions with 3 kinds of ship. It is verified that human-control law is written by formula (7), and constant K_x, K_∽ is changing through the training process. The changing process of the K_x, K_ψ can be approximated by the training process curve, formula (8), which is usually used for description of the training process. Total system (shown in Fig.4. Block diagram) is improved with the change of the operator's characteristics. Using the Nyquist criterion, the change of the total system is understood as the change of the stability denoted by the phase margin. Increasing the training, the system stability converges on the constant value.
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Masayoshi KUBO, Katsuhiko SAITO, Shigeki SAKAKIBARA
Article type: Article
1988 Volume 78 Pages
73-81
Published: March 25, 1988
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The moored ship motions depend on hull forms, mooring systems, the structual type of quay walls and so on. In this paper, particularly, concerning with the ship motions moored along a quay wall which has a slope, two-dimensional analysis proposed by Ijima and the experiments are carried out. The obtained results are summarized as follows: (1) The agreements of the theoretical and experimental results of the ship motions are fairly well. (2) The results obtained on the assumption that a distance between an imaginary boundary line and a floating body is equal to an incident wave length are almost similar to those obtained when the distance is given by Eq. (15). (3) The ship motions moored along a slope are approximated by those moored along a vertical solid quay wall.
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Hisaaki TAKAYAMA
Article type: Article
1988 Volume 78 Pages
83-94
Published: March 25, 1988
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A series of resistance tests were made on 22 scale models of "Wasens, " Japanese coastal fishing boats making use of the 50m tank of Faculty of Fisheries, Hokkaido University from 1984 to 1986, at several constant speeds. Results obtained from the tank tests are the following: i) Coefficients of the total resistances converted from the model tests to five-ton displacement boats, 5γ_T, are reasonably small as 0.04-0.07 in lower speed range of 3-5knots for their prototypes. ii) The peak values of 5γ_T at the last hump range from 0.112 to 0.210 for full loaded condition, the mean is 0.157, and the standard deviation is 0.023. Those values for half loaded condition are from 0.107 to 0.183, 0.135 and 0.019 respectively. iii) The resistance changes with trim, and in general (5γ_T) trim by the head<(5γ_T) even keel<(5γ_T) trim by the stern iv) Regressions of the 5γ_T for even keel with nine variables, i.e., L/B, L/d, B/d, C_b, C_w, C_<υp>, C_p, C_〓 and wetted surface area, S, are given for full loaded condition 5γ_<Tf>=2.187-0.011L/d+0.028B/d+4.883C_b-4.816C_w-5.076C_<υp>+0.336S+1.872C_p+1.813C_〓 and for half loaded condition 5γ_<Th>=-0.013-0.014L/d+0.060B/d-0.525S+0.165C_p-0.407C_w+0.216C_〓+0.046L/B
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Takashi KURODA, Mitsuo YOSHIDA, Norikazu OHNISHI
Article type: Article
1988 Volume 78 Pages
95-102
Published: March 25, 1988
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Social surveys were conducted at 5 mercantile marine schools in Indonesia and the results were compared with those of Japan that were obtained previously by the authors. Respondents were 676 high school or college students for Indonesia and 1440 counterparts, cadets of training ships and seaman working at ocean lines for Japan. The main questionnaire items were to evaluate their nation whether she is a marine nation or not, and to rate images toward the sea, ships and seafarers by a semantic differential method. The results indicated that Indonesian students fostered good images toward their nation and their vocation, and also positive images concerning the sea affairs. In addition, these tendencies were rather remarkable in recently founded schools, and more noticeable than Japan.
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Tatehiko MIKI, Akio IMAI
Article type: Article
1988 Volume 78 Pages
103-111
Published: March 25, 1988
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Minimizing the number of containers which carriers should prepare for the sea-borne containerized transportation is largely due to an effective management planning of containers, especially in the unbalanced trade situation as between Japan and U.S. In this paper two planning models, for decision of the number of containers carriers should possess, and for effective transfer of empty containers, are proposed. Some case studies show the efficiency of these models.
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Yutaka WATANABE
Article type: Article
1988 Volume 78 Pages
113-120
Published: March 25, 1988
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In Japan, it has been obvious that containerized transportation takes a very active part in cargo flows on the sea and in port, but that has been unknown at inland area. This report studies the inland flows of containerized cargo with the object of having thrown light upon the present condition and quantifying the characteristics of it. This study refers to the reports of the investigations made by Japan Container Association. The survey period was for two days in July, 1983 and 1986. The objects of them were to improve the containerized cargoes transported by trucks at inland area. This paper shows the first analysis of this report which analyzed the characteristics of the area of Kyushu.
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Tomoharu MORITA, Kuniaki SHOJI
Article type: Article
1988 Volume 78 Pages
121-127
Published: March 25, 1988
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In this paper, authors study about the behavior of the tank water in rolling of the ship. In the case that the tank water is shallow, calculated formulae are already shown by Chester (1968) or Yoshioka (1968). Experiment was executed by the Ship Rolling Motion Test Device of our chair and compared with calculation. Authors concluded that experimental results on the region of bore (hydraulic jump) are in agreement with Yoshioka's formula on the effect of water depth in the ship model tank as well as rectangular tank.
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Kinzo INOUE
Article type: Article
1988 Volume 78 Pages
129-138
Published: March 25, 1988
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There are two ways to assure the safety of the outside-harbour-refuge under the stormy weather such as typhoon. One is to take the technical countermeasures to avoid the dragging anchor and the other is to drop her anchor at a point appropriate distance apart from the other anchored vessels. In the present paper, the basic idea how to decide such clearance between anchored vessels is discussed and the model to estimate the minimum clearance to be kept around the own vessel against the obstacles such as the other anchored vessels or the shoals is proposed. In the model, the minimum clearance is composed of the three parts of space, that is, the space which is needed owing to the swinging motion before her anchor loses its holding power, the space which is needed while the vessel drifts to the lee after her anchor loses its holding power and the space which is needed during the ship handling operations to recover her own control. These components can be estimated on the basis of the results of the simulation analysis shown in this paper.
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Article type: Appendix
1988 Volume 78 Pages
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Published: March 25, 1988
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Article type: Appendix
1988 Volume 78 Pages
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Published: March 25, 1988
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Article type: Appendix
1988 Volume 78 Pages
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Article type: Appendix
1988 Volume 78 Pages
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Article type: Appendix
1988 Volume 78 Pages
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Published: March 25, 1988
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Article type: Cover
1988 Volume 78 Pages
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Published: March 25, 1988
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Article type: Cover
1988 Volume 78 Pages
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