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Article type: Cover
1986 Volume 74 Pages
Cover1-
Published: March 25, 1986
Released on J-STAGE: January 15, 2017
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Article type: Cover
1986 Volume 74 Pages
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Published: March 25, 1986
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Hideo YABUKI, Michitoshi ISOZAKI, Nobumochi SHIOTA
Article type: Article
1986 Volume 74 Pages
1-7
Published: March 25, 1986
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Being remarkably effective to reduce vibration and noise at the stern, a Highly Skewed Propeller (HSP) is reported, at the same time, to have conparatively less astern power than a Conventional Propeller (CP). By using Training Ship SEIUN MARU, full-scale experiments were carried out in order to evaluate the stopping ability and to consider the maneuvering of a ship with a HSP. In result, the following conclusions are obtained. (1) Stopping time and distance of the ship with a HSP is longer than that with a CP respectively. Differences in stopping time and distance are remarkable, especially in case of small |J_<s0>|(=U/(n・D)). (2) The crash astern performance of the ship with a HSP is considered quite similar to that of a ship with a CP. (3) As for the changing head motion in astern condition, there is no noticeable difference between both ships with a HSP and a CP. (4) During harbor maneuvering of a HSP ship, careful considerations should be given to its stopping characteristics. In other words, it is preferable to avoid excessive headway and to apply a little higher reversing propeller revolution than the nomal maneuvering condition of a CP ship.
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Shigenobu SAITOH, Yuichi YOKOSUKA
Article type: Article
1986 Volume 74 Pages
9-18
Published: March 25, 1986
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A vessel anchoring at single anchor in stormy weather will often sheer violently tacking back and forth across the wind repeatedly, and in the worst case, there is a possibility of dragging her anchor. The study of the remedies against dragging the anchor under stormy weather requires the elucidation of shock load of the anchor cable. From this point of view, we would like to report our newly devised cable tension meter and some knowledges we have acquired using this on the experiments on board. The results of our experiments are as follows: 1. Newly devised cable tension meter can be put to practical use in due consideration of easy handling, cheapness and speed etc. 2. Impulsive cable tension in yawing motion occurs not at the time when her heading coincides with the cable direction as has ever been known but much later when the cable direction stands at about 50°to her heading. 3. The cause of one occurrence of impulsive cable tension in yawing motion shoud be considered not only in terms of ship motion but also in terms of 'the snapping phenomenon of the cable in the sea' which is caused by ship motion. In this sense, impulsive cable tention is to be called 'snap load' instead of 'shock load'.
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Yoshimi NAGAO, Katsuhiko KURODA, Kinzo INOUE, Keinosuke HONDA
Article type: Article
1986 Volume 74 Pages
19-28
Published: March 25, 1986
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The present paper proposed a probability model for evaluating the safety level of a ship moored at anchor under stormy weather such as typhoon. It is well known that JIS-type anchor loses its holding power after making rotate the palm round the shank over 45°. Based on the results of model test, the distribution of the maximum dragging distance (Y) until the anchor loses its holding power can be approximated by the normal distribution. Accordingly, the probability that the anchor loses its holding power during the ship is dragging her anchor can be calculated as follows; P_<υf>=∫^X_<-∞>f(Y)dY where, X is the dragging distance within a certain period of time and can be estimated from the relation between the load acting on the anchor and the dragging distance which were derived from the results of model test. Proposed model gives us many information regarding with the safety level of the mooring system, therefore, it is useful for decision making on the engineering planning and design of the mooring system under stormy weather.
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Kuniji KOSE, Hiroyoshi HINATA
Article type: Article
1986 Volume 74 Pages
29-34
Published: March 25, 1986
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Many kinds of indices have been proposed to express ships' maneuverabilities, such as K, T values derived from well-known zig-zag tests, steady turning characteristics from spiral or reverse spiral tests and so on. These are very convenient for expressing ship abilities in simplified maneuvering motions. But it is easily understood that these are not adequate for performance indices of maneuvering motions in harbours. In the present report, a new concept is proposed to express maneuvering performances of ships in harbours. Gathering and analysing ship handling plans for approaching to and departing from many berths, it is pointed out that various maneuvering motions in harbour are classified into the following four groups: course keeping and course changing with/without speed change, turning and drifting to the lateral direction. Ship performances in these motions are called as "elemental performances of harbour maneuvers" in the present report. The performances are good indices for ship maneuverabilities in harbours.
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Akio IMAI, Tatehiko MIKI
Article type: Article
1986 Volume 74 Pages
35-42
Published: March 25, 1986
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It was recently announced that container ports other than major container ports already built will be constructed all over this country. However, seaborne containerized cargo will not be expected to increase without inprovement in the world trade situation because almost all ocean liners have been containerized except for one toward developing countries. A model of shipper's choice of container ports is discussed in this paper, in order to estimate the performance of these ports. In this model, the proposed ports for shippers are chosen due to frequency of shipping cargo typically showing shipper's behavior, frequency of port calls and inland transportation cost charged by shippers. The accuracy of this model is checked by comparing with container distribution data. The analysis shows that the proposed choice model may be successfully applied.
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Fujio HORI
Article type: Article
1986 Volume 74 Pages
43-49
Published: March 25, 1986
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In order to investigate the wind-action containers, by making use of a wind generator closed-type, the author carried out the model test on a container and the simulation of stacked containers in the PC-11 Container Yard (Kobe Port Island). Models for getting the wind force coefficient are 1/20 scale of 20 feet dry container and simulation models are 1/40 scale of 40 feet dry container. The results of experiments were as follows: (1) As compared with results of another methods, I could confirm the wind force coefficients. (2) When the wind blows at right angles to the front surface of container (θ=0°), these values are drag coefficient (C_d)=1.025, lift coefficient(C_l)=0.581 respectively. The result by the simulation tests showed that in the range of θ=15°to 30°stacked containers started to slide by lower wind velocity.
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Yoshiro IMAEDA, Sukita NAKAHARA, Kojiro MOTOMURA, Masato HAMAGUCHI, Su ...
Article type: Article
1986 Volume 74 Pages
51-60
Published: March 25, 1986
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An experimental study of seasickness was carried out on board a training ship. The estimation of acclimatization effect was derived from the normalized incidence of motion sickness. The correlation between MSQ scores and the degree of motion sickness incidence were decreased as the day of cruise went on. Thus, the acclimatization effect were estimated by the correlation analysis. The relationships beween the degree of motion sickness and related several factors (such as motion sickness experiences, general status, several behavioral characteristics, psychosomatic imbalance, etc.) were also investigated by correlation analysis and by multiple regression analysis.
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Masayoshi KUBO, Toru SAWARAGI
Article type: Article
1986 Volume 74 Pages
61-69
Published: March 25, 1986
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According to the statistics, most labor accidents happen in the mining, forestry, and ship cargo handling in this order in Japan. The danger of cargo works is mainly caused by the unstable foothold due to roll motions of a ship. It is well known that the roll motion is induced by the free oscillations accompanying with cargo handling as well as by the waves. From the field observation, it is found that the large inclination of the ship and free oscillations are followed by heavy cargo handling on a small ship, and they always make the cargo works dangerous even in a harbor. We have already investigated the damping of ship motions by using a dash-pots mooring system in waves. In this paper, how this mooring system is also effective on cargo handling is studied, and fundamental factors to design an appropriate dash-pot are shown.
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Yutaka WATANABE
Article type: Article
1986 Volume 74 Pages
71-78
Published: March 25, 1986
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In everyday life we often use petroleum, as light oil and gasoline, which are consumed to fuel. These oil are transported by barges and small tankers that sail up a river and a water way from oil refinery near the port to inland tank. An outflow accident of the oil which happens at the situation is not little observed, since its scale is not large, but it is necessary that we should study transformation of the oil after it, for it is possible to suppose there are unusually crowded areas along there. From this point of view I made an experiment, for which a water tank was made, that flowed light oil and gasoline on the surface of the water. As the result of the experiment it was proved that the motion of petroleum was very fast. This report gives an outline of the experiment.
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Shihei NOMURA, Masanobu TAHARA
Article type: Article
1986 Volume 74 Pages
79-88
Published: March 25, 1986
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This paper deals with measurements of maneuvering tracks of a ship using a doppler log. Maneuvering tests were executed on Training ship "YUGE MARU". Datum from the doppler log and the other necessary sources such as yaw rates, rudder angles and etc. were recorded and analyzed by the computer recording and plotting system. Taking the time lag and the sensor installed error into consideration, her tracks were calculated by the numerical integration. For the purpose of checking the accuracy, her calculated arrival points were compared with the actual ones. The results showed good agreements and this measurement system will be able to be put into practical use.
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Hiroshi OHKUBO, Toshiaki SATO
Article type: Article
1986 Volume 74 Pages
89-97
Published: March 25, 1986
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This paper describes the operational coverage at the phase III Global Positioning System (GPS) for the full 18 satellites plus three spare satellites in Japan. The result is that there will be one or two poor accuracy periods in Japan after the GPS schedule is completed. The position accuracy can be obtained by multiplying the user equivalent range error by a position dilution of precision (PDOP). It should be noted that this estimate of accuracy is for a point solution to the GPS ranging equations and can be improved with the kalman filter. The kalman filter will be particularly effective in reducing the random errors. It has been demonstrated that the reducing factor is at least 1/3 by computer simulations.
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Nobuyoshi KOUGUCHI, Yasuo ARAI, Yumio YONEZAWA
Article type: Article
1986 Volume 74 Pages
99-107
Published: March 25, 1986
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The non-homogeneous earth surface causes warpage of the Loran-C signal and induces a bias error on the measurements for the time of arrival. The purpose of this paper is to decrease this error, using the correction value calculated from the Envelope to Cycle Difference of the received pulse signal itself. In our previous study, we assumed the ECD variation model for the mixed propagation path. To appreciate that model and to indicate the advantage of the correction values, the experiment was carried out in the domain of the 9970 Loran-C chain. Using the results of this experiment, we can describe as follows, 1. The ECD had a correspond value at the same position, in proof of repeatability. 2. There were significant changes in the ECD values over the land propagation. 3. The fixed position by the corrected time differences from above method were closer to the fixed position by NNSS than case of non-corrected one.
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Yuji IKEDA
Article type: Article
1986 Volume 74 Pages
109-116
Published: March 25, 1986
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This paper deals with the experiments on the Collision Avoiding Behaviors by experienced navigators for the target approaching from side in the restricted visibility. The experiments were carried out on the condition that (1) Own ship was proceeding at 15 k't (S/B Full ah'd) in the ocean, (2) Target ship's initial position were at 10 miles of port side, and time to collision were 45 minutes, (3) Own ship could maneuver with no restrictions. The results of the experiments were as follows. (1) The tendency of altering course were not certain for the targets of forward of abeam. (2) Marked tendency of right turn were observed for of abeam and after of abeam. (3) The distance to the targets of taking action was 5.7 miles, and desired CPA was 1.8 miles (mean value). The effect of right turn for the target of near abeam is generally not positive nor remarkable, hence, the author propose a method to clear these encounters. The method is to shift the relative motion line parallel to original course of own ship. The boundary of this method is that the speed is less than the product of own speed and secant of relative bearing.
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Hayama IMAZU, Takeo KOYAMA
Article type: Article
1986 Volume 74 Pages
117-123
Published: March 25, 1986
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It is necessary to valuate a decision-making model for collision avoidance, for investigation of a competence of navigators and collision avoidance systems. The elements of the valuation method are setting of ships encounter models and appraising the decision-making model. First, a setting of ships encounter models by simulation method is discussed. Then, valuation method of decision-making model by using these ships encounter models is presented.
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Tadashi NARITA
Article type: Article
1986 Volume 74 Pages
125-137
Published: March 25, 1986
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In the latter half of the previous paper III, the author has reported a theoretical study of several characteristic problems concerning the FS (Free Surface) mechanizations of inertial navigation. This report IV continues the same sort of investigations and treats: 1. Two methods of realizing the free surface without using the accelerometers. One method is to slave the platform surface to the free surface of liquid in a container using non-contact distance sensors and servo-motors. The other simply make use of one or two spirit levelings with the aid of servo-motors. 2. Relations between the errors δβ_j, of the angle measuring sensors and those of the calculated specific force components a_x^n (east-west component) and a_Y^n (north-south component). Here β_j is the direction cosine of the angle a_j between the j-th reference axis and the platform axis Z_p. It was found that the type IN mechanization has a singularity at λ=0, λ is the lattitude, owing to the coincidence of the earth axis Z_E and the north-south axis Y_n, on the equator. This singularity can be removed if the mode of operation is changed from IN to NS or I (1) in the neighborhood of this lattitude. 3. A probabilistic law for obtaining a reasonable value of a_X^n when the calculated value of this component is very small or even imaginary, i.e., when |(a_x^_r|≅0. The reasonable value turns out to be (a_x^n)_r=0. This rule is to apply to the types NS, I (1) and IN mechanizations where the east-west component is calculated by the formula a_X^n=sgn(a_X^n)√<(a_Z^p)^2-(a_Y^n)^2-(a_Z^n)^2>. Here sgn(a_x^n) means the sign of a_X^n, a_Z^p is the negative of the total specific force, and a_Z^n is the vertical component of the specific force vector a. In conjunction with this, the term "insensitive zone of a_X^n around zero" is introduced, which is to be considered a common defect of the types NS, I (1) and IN mechanizations. It is of course desirable to reduce the width of this zone as small as possible, and an appropriate and sensible means for attaining this objective is to use high performance angle measuring devices for α_j thus reducing the errors in β_j. However, concerning the type IN mechanization, this defect can be overcome rather easily by a modification of the mechanization. This revised version which may be called the type IN (R) mechanization has no insensitive zone and does not require the sign monitoring of a_X^n.
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Yasuyuki SHIRAI, Kiyotaka SAITO, Hiroshi SUZUKI
Article type: Article
1986 Volume 74 Pages
139-146
Published: March 25, 1986
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The authors have been studying about an immovable type magnetic course indicator with an electrical deviation corrector. In process of this study, characteristics of the magnetic sensors and the values of ship's magnetic field became neccesary to be precisely measured. We designed a magnetic sensor of flux-gate type and a set with three axes about (fore and aft, port and starboard, top and bottom), then examined about its characteristics. While, ship's magnetic fields are meaured on UMITAKA-MARU and HAKUSAN-MARU at sea. This paper describes ability test for magnetic sensor that make use of three dimensional magnetic field detectors and measured results on ship's magnetic field using the new instrument.
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Article type: Appendix
1986 Volume 74 Pages
App1-
Published: March 25, 1986
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Article type: Appendix
1986 Volume 74 Pages
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Published: March 25, 1986
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Article type: Appendix
1986 Volume 74 Pages
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Published: March 25, 1986
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Article type: Appendix
1986 Volume 74 Pages
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Published: March 25, 1986
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Article type: Cover
1986 Volume 74 Pages
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Published: March 25, 1986
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Article type: Cover
1986 Volume 74 Pages
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