The Journal of the Nautical Society of Japan
Online ISSN : 2433-0116
ISSN-L : 0466-6607
Volume 44
Displaying 1-31 of 31 articles from this issue
  • Article type: Cover
    1970 Volume 44 Pages Cover1-
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
    JOURNAL FREE ACCESS
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  • Article type: Cover
    1970 Volume 44 Pages Cover2-
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
    JOURNAL FREE ACCESS
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  • T. Hiraiwa, G. Kobayashi, K. Masuda, S. Yamamoto
    Article type: Article
    1970 Volume 44 Pages 1-6
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    To analyze the effects of wind and wave upon a ship's speed and course is a very important problem from the view point of navigation. The authors experimented them aboard the Oshoro Maru (1181 G/T) in the Bering Sea. The experiment 1. The ship's courses were given 12 directions every 30°in regard to the direction of the wind. 2. The corner reflector connected to the salmon gill-net was selected as the datum point of experimentation. In this case, the reflector was allowed to drift equally with the ship by ocean currents and drift currents, but felt no effect from the wind. 3. As shown in Fig.1, the observers on the ship measured the distance and bearing of the reflector by radar at observation points A & B, and calculated the direction and distance of the ship's run through the water. And by the same way they repeated such observations on the 12 courses every day. 4. Sailing time of one course was planned to be 10 minutes. The result 1. Relation between the direction of wind wave and ship's speed We divided the data into three groups according to weather conditions and showed them in Fig.2, and as mean values, formed smooth curves, following approximately the cosine curve. 2. Relation between the direction of wind wave and the steering error The error of steering is gotten as the difference between the planned course set in the gyro auto pilot and the mean value of course recorded by the course recorder, as shown in Fig.3, in connection with wind directions. As shown in this figure, the ship's course drifted to the right regardless of wind wave directions. 3. Relation between the direction of wind and lee way The lee way corresponding to each wind direction is shown in Fig.4 in relation to wind velocities. The coefficient of the lee way must be considered with some allowance from the view point of the number and deviation of data, however under usual sailing and weather conditions it is to be desired that navigators deal with the lee way with equal care as compared with the steering error, accuracies of estimated ocean currents, drift currents and tidal currents.
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  • T. Hiraiwa
    Article type: Article
    1970 Volume 44 Pages 7-16
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    The author had already analyzed the navigational records of several ships and investigated the effects of the winds and waves on ships' speeds, but each ship was different from each other in type, size, condition, ability, etc., it was not possible to formulate any universal rules. Hereupon, if I make the assumption that speed reduction of each ship follows a common formula, I can express an experimental equation as to speed reduction corresponding to sea condition, and it is also easy to compare the characteristics of any ship. The assumed equation to suit the object must be simple in form within the limits of the possible, so that a ship's speed V be given in the following formula, V=a-bcosθ, and can be applied to three ocean-going ships. As a result, the coefficients a, b are kept in line with certain curves as shown in Fig.4 (a)(b), on the assumption that a=a'-cB^n, b=dB^m, those points fitting closely. Accordingly, the speed equation is expressed as follows: speed=a'-cB^n-dB^mcosθ (where B: Beaufort scale, θ: Wind direction) Secondly, as to the three coasting vessels, the coefficients a, b are shown in Fig.5 (a)(b), and they are expressed by the following equations: a=a'-c'D^n, b=d'D^m, accordingly, speed=a'-c'D^n-d'D^mcosθ (where D: scale of wind waves) Furthermore when I indicate a ship's speed in connection with a wave height (H), it is expressed thus: speed=a-bH-cH^mCosθ, as shown in Fig.6 (a)(b) and Fig.7 (a)(b).
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  • K. Shibata
    Article type: Article
    1970 Volume 44 Pages 17-22
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    The air bubbles occur in various forms in the sea, and they are generated also in wakes of ships where they are known to remain for long periods of time. Especially, great amounts of air bubbles are generated in the dock water by pouring water and by discharging currents of tag-boats in which high value of ultrasonic absorption is presumed. Observations of ultrasonic absorption in dock water were carried out in the No.2 Dock of Nagasaki Ship Yard of Mitsubishi Heavy Industry Co., in February 1970. After observations, the absorptions caused by air bubbles and others in dock water were estimated as 0.05dB/m to 0.35dB/m, and 0.13dB/m in average. Those values were far high beyond the predicted one.
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  • K. Shibata, H. Nishinokubi, K. Amagai
    Article type: Article
    1970 Volume 44 Pages 23-28
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    On an echo survey under streaming, the echo amplitude from sea-bed showed some variations. HASLETT [1] reported that the observed variation of echo amplitude may be attributed, mainly, to: (a) the geometric effects of the beam patterns, due to rolling and pitching, (b) the variation in coupling between the transducers and the water, and, (c) variations in the reflectivity of sea bed. It is interesting to note the variation of echo emplitude from seabed due to ship's motion. Some field observations for this study were made with an echo-sounder operating at a frequency of 200kHz on board the bull trawler, Tokai-Maru, No.1, on a steady course of beam wind at a speed of 4m per min near the Socotra Rock in the East Sea in October 20th 1968. The sea-bed was very flat and consisted, mainly, of fine sand. Recording of the echo, pitching angle of the trawler and also rolling angle were made on a magnetic tape recorder (TEAC, R-200). Individual echoes and angles of pitching and rolling corresponding in time to the respective echo were later analized for 700 series of the data in the laboratory. We found on the results that there were hardly direct relation between the echo amplitude and ship's motions but also with some relationship on the phase consideration.
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  • K. Kawahira
    Article type: Article
    1970 Volume 44 Pages 29-36
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    First, the writer drew the contours of constant probability density of Sun-Run-Sun's Meridian Altitude on the Mercator chart, and, using the chart, made a serviceable diagram showing the most suitable time for a morning sun sight for navigators. Secondly, supposing that the navigator had made the morning observation at the most suitable time, the writer drew parallels of the constant probability density of Noon Position on the ditto chart, and by comparing these of Loran C fixes with the previously mentioned parallels, the writer tried to make a practical chart by which navigators could select the appropriate triplets of Loran C stations or Sun-Run-Sun's Meridian Altitude to obtain the most accurate Noon Fix in the Pacific Ocean.
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  • A.M. Sugisaki
    Article type: Article
    1970 Volume 44 Pages 37-40
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    The auther defined the traffic capacity of the channel using the degree of freedom of the operational parameters such as speed, course etc. and devised the method of obtaining the conversion traffic capacity against the volume of ship. Futhermore, he showed the results of the simulation according to his method and definitions.
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  • K. Ohtsu, A.M. Sugisaki
    Article type: Article
    1970 Volume 44 Pages 41-47
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    We researched meeting numbers of ships in the Uraga Channel by a simulation method of computer. In this paper, we gave a definition to the word 'meeting, that the other ships touches the hands which are hold out from the ship observed to starboard and port beam directions or fore and aft directions, having a limit length depending on the length of ship observed. We executed the simulaions for 24 hours with the digial computer FACOM 270-20. According to the results, the zones where meeting numbers are the most frequent are near the No.2 buoy and No.4 buoy.
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  • Y. Fujii
    Article type: Article
    1970 Volume 44 Pages 49-58
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    Since the size of the effective domain is an important quantity for the estimation of traffic capacity, it has been studied by measuring two-dimensional separation between ships. A theoretical estimation for the effetive domain is tried by defining it as the totality of (R_1^^^→-V_2^^^→t) expanded with a radius equal to that of the geometrical collision radious over a time range from t=t_0 to t=t_0+T, where R_1^^^→ is the position of a keeping-way vessel, V_2^^^→ is the velooity of a giving-way vessel, and T is the sum of time length necessary for the detection of the change in the velocity of the keeping-way vessel and that for the evasive motion of the giving-way vessel. When R_1^^^→ is equal to R_1^^^→_(t=t_0)+V_1^^^→(t=t_0)t, the effective domain is equal to the manoeuvable limit. However, the velocity of the keeping-way vessel is not guaranteed to be constant, and consequently, it is given as a representation of a group of equi-probability curves. These equi-probability curves may be obtained by the statistical investigation of behaviors of vessels. The time length, T, is obtained from the distribution of motional characteristics of vessels and the minimum value should be about 5τ_1, +3τ_2, where τ is the characteristic time and is equal to (ship length)/(speed) and suffixes, 1 and 2, correspond to the keeping-way vessel and giving-way vessel respectively. Above consideration allows derivation of formulea for the effective domains for different encounter condition, e.g., crossing, taking over, by adopting equi-probability curve corresponding to a probability of 99.99%, which is obtaned from the study of collision probability.
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  • K. Yamada, K. Tanaka
    Article type: Article
    1970 Volume 44 Pages 59-65
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    The traffic capacity of a network of waterways is important for the design of a canal system in a harbor. A program for the simulation of traffic flow is studied as the first step for the evaluation of the capacity. Since the data on the traffic in the canal system of Tokyo Harbor are compiled, the simulation is applied for the Keihin Canal and its vicinity in the system, where there are curves and a T-shaped crossing. The distributions of the ship size and speed are so determined to simulate the real ones and the time of ship arrival is assumed to follow the random distribution. The unit time for the simulation is determined as 0.8τ_mean' i.e., one tenth of the time necessary to proceed 8L_mean' the semi-axis major of the evasive domain, Where L_mean is the average length of ship and τ_mean is the average characteristic time, L_mean/L_mean. When no collision, stranding, nor deep violation of center line is expected in a tim length of 8τ_mean' each ship is moved forward by 0.8τ_mean V where V is the speed of each ship. However, when a ship is expected to collide, strand, or violate the center line, the change in direction is examined and followed. If no suitable steering is expected to avoid the danger, retardation is examined. An example of the distribution of ship traces is shown as the result simulation.
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  • K. Tanaka, K. Yamada
    Article type: Article
    1970 Volume 44 Pages 67-72
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    The observation in the separation of various size of vessels whose lengths are different considerably was carried out with a mm wave radar and a multiexposure camera, and the following results were obtained. The size of effective dowain is given as [numerical formula] where r_pq and S_pq are the length and width of the effective domain respectively and subscripts, P and q, refer to preceeding and following vessels, respectively. The ratio of the area of effective domain of a large sized vessel and that of the standard one is defined as "the equivalent number." Above equation gives that the equivalent number is proportional to the square of the length of vessel.
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  • H. Nakajima, K. Shoji, Y. Iijima
    Article type: Article
    1970 Volume 44 Pages 73-79
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    As well known, the search operation of a ship in distress is extremely difficutlt in rough sea. Especially it is almost impossible to discover life boats or castaways by eye at night or in foggy weather. Under such circumstances, if the life boat and castaways are equipped with some object which might effectively reflect radar wave, the search by a radar becomes possible all the time and life rescue operation will be carried out effectively. From the point of view, we made several sorts of such corner reflctor which might be easily equipped with life boat or castaway, and experimented the effectiveness and radar cross section of such reflectors.
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  • K. Kimura
    Article type: Article
    1970 Volume 44 Pages 81-91
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    Position Determination Experiments by the Navy Navigation Satellite System have been made at the Electronic Navigation Laboratory since fall 1969. First, this paper describes frequencies and modulation forms of signals transmitted by satellites. The paper also gives the outline of recieving equipments used by the Laboratory and the method of caluculation for posion fix. The results of the experiments during 24 hours and one month are shown in Figures 10 and 11. The RMS error of position determinations was about 600 meters.
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  • H. Yamanouchi
    Article type: Article
    1970 Volume 44 Pages 93-96
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    Since the speed measuring radiosystem can be used for limited visibility, it has been adopted widely by shipyards and many evaluation tests of the radiosystems are applied to our laboratory. The speed data obtained by the radiosystems are usually compared with those obtained by the "Mile Post Method" which may be influenced by human factors. Therefore, the photographic methods are developed for more objective evaluation tests. (1) The differences of speed data by the radiosystem and those obtained from photographs of mile posts and crystal clock were less than 0.1%, which is remarkably small compared with figures of 0.2%〜0.3% by the conventional "Mile Post Method". This suggests that the photographic speed measurements can be applied for general speed measurements when high accuracy is requested. (2) The differences of speed data by the radiosystem and those by the photographs of ship and the crystal clock were less than 0.2% for a ship of 127 meters long. This method is used for the evaluation of the system in a short range.
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  • S. Nagasawa
    Article type: Article
    1970 Volume 44 Pages 97-103
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    LooK-out should be vigilant, and constant vigilance is greatly required. I want to find out general rules and legal value of Look Out, through The Dicisions At The Maritime Disaster Inquiry Agency.
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  • G. Fujisaku
    Article type: Article
    1970 Volume 44 Pages 105-111
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    Making an attempt to show a concrete guide to practical affairs, signal and conduct of a vessel in the neighbourhood of a fog bank were considered. In this paper were shown chiefly the cases for restricted visibility in the neighbourhood of a fog bank to correspond to the fact of restricted one in Regulations and the points for signal and conduct of a vessel under actual circumstances and conditions to shift to lawful ones in Part C of Regulations.
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  • Y. Amemiya
    Article type: Article
    1970 Volume 44 Pages 113-123
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    It was calculated each P.D.C. of 15 items added physically and directly to the container cargoes during processing from vanning to shipping by the productive implements and labor efficiency. The laborers' working hours and wages were fixed at present and some schemes and problems for the rationalization of container system were investigated parameterically. The results are reported as follows: 1. The container transportation form using the trailers shoud be planned variously before the curtailment of the drivers' number. 2. Compared the researched quantity of operating cargoes with the number of container berths being planned in Japan, the excess of supply about the number is considered. 3. The lower P.D.C. of the road, straddle carrier and labourers in port hinders lowering the total P.D.C. 4. The most suitable scheme of the container transportation is to balance each P.D.C. added to cargoes by the processing parts.
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  • Y. Inaba
    Article type: Article
    1970 Volume 44 Pages 125-133
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    The ship heels inwardly toward the center of a turning circle about her fore and aft longitudinal axis immediately after her rudder is put over, and then heels on the opposite side as shown in Figs.4 and 7. This is due to the fact that the transverse changeful forces act at different vertical positions. The greatest angle of heel involves a significance for the safety of a ship. The author has developed some treatments on dynamical investigation by means of analog computer, and got calculations regarding the following subjects: (1) Variations of heeling angle in accordance with the change of metacentric height. (2) Variations of heeling angle in accordance with the resistance to rolling of a ship. (3) Variations of heeling angle in accordance with the acting of periodic force. (4) Variations of heeling angle effected by initial heeling when ship's rudder is put over. (5) Variations of heeling angle in accordance with ship's rudder was put back suddenly while turing. The ratios of heeling angle to the static angle of heel to which the ship finally settles down are discussed.
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  • Y. Inaba, Y. Sakamoto
    Article type: Article
    1970 Volume 44 Pages 135-140
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    In order to investigate the safety and manoeuverability of a ship, it is necessary to clarify the effects of wind on them. The wind tunnel experiments were carried out with an image model of above and under-water portions of the training ship Oshoro Maru, changing the direction of wind relative to the model over the whole ranges. The forces acting on them were respectively measured. In the first half part of this paper, there are given the results of them as shown in Figs.2, 3, 4, 5 and 6. A ship may be said to hold manoeuverability when she is fully possible to turn to both sides. Manoeuverability become impossible at high ratio (wind velocity/ship's speed), viz. at higher wind velosity as compared with ship's speed. In the latter half part, the motion of Oshoro Maru under strong wind was analyzed using the above experimental data, and the range where she is manoeuverable, and those where she turns both windward and leeward are respectively obtained as shown in Fig.8.
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  • R. Kawashima
    Article type: Article
    1970 Volume 44 Pages 141-151
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    This is the study on a statistical analysis of ship oscillation due to the ocean waves on the open sea by the use of a specially defined correlogram. In this paper, the motion of equation for ship oscillations due to ocean waves was assumed to be the linear stochastic differential equation (Eq. No.2). In the solution of this equation when the random input with the Flat Spectrum was applied, the equation of the correlogram (Eq. No.6) was determind. In accordance with the above mentioned theory, the practieal data processing procedure through a specially deviced prewhitening method helped to define the average correlogram. For the application of this theory, the average correlogram was calculated on the ship motion data and examined by Qenouille's test and discussed. These results are shown in Fig.2 and Tables 3 and 4. Adequate results were obtained.
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  • A. Iwai, H. Kugumiya, K. Otsu
    Article type: Article
    1970 Volume 44 Pages 153-159
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    In this paper, the authors describe the experimental results upon the hydrodynamic effects on the course keeping of ship passing near by the bridge post crossing over the channel. Model experiments have been carried out on 1/100 and 1/200th scale models of square section bridge post and full type of large tanker in circulating water tank, and the hydrodynamic moment and forces acting on the ship due to the stream around the post were measured. From the experimental results, the authors recommend as follows ; To keep the ship's course by steering with less than 15 degrees of rudder angle against the hydrodynamic interaction between ship and bridge post, ship must take her course of perpendicular to the bridge line with a ship's length of transeverse clearance.
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  • H. Kanda
    Article type: Article
    1970 Volume 44 Pages 161-167
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    The ship light display is regulated for ship collision prevention in accordance with international rules. Whether ship lights are adequately recognizable or not is a vitally serious problem as it has direct influence on prevention of ship collision. A study was made this time on the recognizability of ship lights. 1) Experiment on the chromatic threshold of a spot luminescent source. The result proves that the average chromatic threshold of five subjects is 6.57×10^<-8> l_x for white, 2.03×10^<-8> l_x, for red, and 10.12×10^<-8> l_x for green, respectively. Provided, however, that selection was made from color filters with the standard chromaticity commonly adopted by ships. Where the ship-light recognition distance was calculated, based on this experimental result, and on the assumption that the electric bulb of a ships light is 40 Watt, the respective distances were obtained as being 5〜7.2 sea-miles for an incandescent lamp, 4〜5 sea-miles for a red lamp, and 2.3〜2.8 sea-miles for a green lamp under very clear atmospheric complying with the atmospheric conditions stipulated by the international visibility standard. Attention must be directed to the fact that it is especially difficult to recognize a green light. 2) Experiment on the recognizability of ship lights classified according to the respective patterns. The ship light patterns were selected in conformance to concrete examples stipulated by the ship collision preventive law. In I group, a white lamp was combined with a red lamp while in II group, a white lamp or a red lamp was combined with a green lamp and to the subjects were made to recognize these patterns while experimentally performing the simulation. In the case of the II group in which a green lamp is combined, the result proves that it is difficult for the subjects to recognize the green lamp, remarkably reducing the recogniton rate.
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  • T. Yamada, K. Yoneda, Y. Nishiyama, A.M. Sugisaki
    Article type: Article
    1970 Volume 44 Pages 169-176
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    The authors adopted the transportation process of exporting general cargoes as total system and built its system model and analyzed physical distribution cost which was calculated through computer simulation. The object of model was selected the transportation between Japan and U.S.A. excepting inland transportion and imagined ports were Kobe, Yokohama, San Francisco and Los Angeles. The results of case study through simulation, wtich should be managed for the sake of reducing the physical distribution cost, were as follows: (1) The elements affected on physical distribution were ship's D.w., ship's speed, cargo handling rate, number of ships and number of berths. And they were correlative on each other, so it should be managed to make them reasonable in accordance with annual tonnage of cargoes delivered in management of ships and port facilities. (2) It should be managed to reduce ship's berthing time for cargo handling and ship's waiting time for berthing because the influence of demurrage is very high. For the purpose of reducing, it must be control equally the level of aforementioned each element. (3) The utilization factor of 10 berths of each port should be kept between 0.6 and 0.8. (4) The percentage of P.D.C. in terminals against total P.D.C. is considerably high. This points out the necessity of rationalization of physical distribution process in port area.
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  • Y. Terada, Y. Nishiyama, T. Yamada
    Article type: Article
    1970 Volume 44 Pages 177-182
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    The states of ship's waiting for berthing are increasing in number, because congestion problems in Japanese many ports are becoming worse year by year. Waiting time has a great influence not only on the ship owner's disadvantage but also on physical distribution cost. So that authors tried to solve a congestion problem through simulation which using the change of parameter of elements -the average number of the ships entering the port in a day, the number of berths, the amount of the cargo loaded on each vessel and the cargo handling rate- on basis of the present situation's data. As a result, Ship's waiting time would be reduced to nothing if the utilization factor of berth is kept within 0.6 except at the nighttime when all the vessels are prohibited to enter port. It is necessary to consider the four elements on the planning stage of berth and ship's operation as the four elements are in the correlation.
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  • A. Sugiura
    Article type: Article
    1970 Volume 44 Pages 183-190
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    Our Rules of Ship's Lifesaving Appliances, under the provisions of 1960 International Convention on Safety of Life at Sea, are already out of keeping with the present state of affairs that those monstrous and highly efficient or automatic controlled vessles are appearing rapidly. There is no denying the fact that many lives were lost in such enormous vessel disaster. Accordingly the auther had a try at the improvement on lifesaving apparatus with reference to the answers of an opinionaire from seamen. That is a Turtle-boat, which has both functions of lifeboat and lifejacket. And the author tried to design a new type lifesaving apparatus named Kappa-boat, too.
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  • H. Tani, M. Enokida
    Article type: Article
    1970 Volume 44 Pages 191-201
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    A practical method of analysing the acceleration and deceleration of ships is presented with special reference to large vessels. The motion of ship is described in terms of the advance-coefficient of the propeller which gives the rate at which the propeller advances through the water during its unit revolution per second. The use of time constant T is recommended as a reasonable measure of acceleration and deceleration of ships both in a practical and theoretical point of view. In consideration of lack of the published data, the results of some trial calculations are presented.
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  • H. Tani
    Article type: Article
    1970 Volume 44 Pages 203-208
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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    As a large vessel diminishes speed in the channel, she commences to lose control of her bow, and tugs are used to push against the bow of the vessel. Though the tug can work with greatly reduced speed of the large vessel, if the latter can not kill her headway sufficiently, this is seldom the case. The present paper determines the limits of the speed of the vessel within which the effective work of tugs can be expected, by solving the subject as the problem of the static equilibrium. Calculations are made for the particular cases of 4, 000 shp tug with controllable-pitch-propeller and 1, 950 shp tug with Voith-Schneider-propeller. The result shows that the c.p.p. tug can work most effectively with about 4 knots of headway of the large vessel, while the v.s.p. tug with about 3 knots.
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  • Article type: Appendix
    1970 Volume 44 Pages App1-
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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  • Article type: Cover
    1970 Volume 44 Pages Cover3-
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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  • Article type: Cover
    1970 Volume 44 Pages Cover4-
    Published: December 30, 1970
    Released on J-STAGE: September 26, 2017
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