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Article type: Cover
1960 Volume 23 Pages
Cover1-
Published: December 25, 1960
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Article type: Cover
1960 Volume 23 Pages
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Published: December 25, 1960
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H. Suzuki
Article type: Article
1960 Volume 23 Pages
1-9
Published: December 25, 1960
Released on J-STAGE: September 26, 2017
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The magnetic compass card must be always steady about the horizontal axis passing through the diameter of it even on the conditions where the ship is heavily rolling. The dynamic stability of the directional system is chiefly due to h (the distance from the compass pivot to the plausible center of gravity weight concerning the directional system in the compass liquid) and W (the weight of system in the liquid). In our experiments, the mesurement of θ (the inclination angle of magnetic compass) were made by changing the value of hW. And by considering the motion of directional system about the horizontal axis of compass card as the pendulum movements, we get the following linear differential equation of second order concerning the inclination angle θ. [numerical formula] In order to make dynamic stability stable, it is necessary that the damping ratio ζ is relatively larger, or the natural frequency of the system is lower than the disturbance frequency imposed to the system.
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H. Suzuki, N. Fukuoka, M. Shinohara
Article type: Article
1960 Volume 23 Pages
11-16
Published: December 25, 1960
Released on J-STAGE: September 26, 2017
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For any type of compass card available aboard it must of course be guaranteed the circumstance that the geo-magnetic field in which the ship is situated is virtually negligible. Moreover, the drag of angular restoration the card inevitably shows as the ship turns is also desired to be as small as possible. Though this angle may be minimized by reducing the viscosity of the liquid filling the compass bowl, the card will also be made fidgety thereby showing an enlarged deflection peak and shortened period of swing. In order to solve this dilemma a few types of filament damper were examined of the efficacy of their application. The present paper deals with the effect of such dampers reflected on the behavior of a compass operated in distilled water as a model liquid of low viscosity. The test was carried out for various values of viscosity (0.71-1.31×10^<-2>cm^2/sec) realized by changing the temperature of the distilled water. The result of the test indicates that if the value of d 0.31 of the dampers is about 50 the damping character would be best one in this compass liquid which has above mentioned range of kinematic coefficient.
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Y. Nakajima, K. Shoji, Y. Iijima, T. Yano
Article type: Article
1960 Volume 23 Pages
17-21
Published: December 25, 1960
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The writers have devised a balloon type of reflector, and weasured the echo-power of this experimental reflecton. Then they have examined the radar cross section of it, and then assumed the echo-power of the reflector located on a life raft with respective heights of 3 meters and 7 meters. Secondly, they thought the cross section of a streched triangle type of reflector, and measured the echo-power of this type reflector and of wooden reflectors pasted with several sorts of the "Scotchlite" Reflective Sheeting.
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Y. Maehara, Y. Nishitani
Article type: Article
1960 Volume 23 Pages
23-31
Published: December 25, 1960
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Marine radar set at present uses the system of the P.P.I. presentation, which rotates continuously the scanner transmitting pulses in a narrow horizontal beamwidth, and which detects the targets in all directions while the set is in operation. Some seconds, however, are required for each revolution of the scanner, and the ship being under way for the time, and distortion of radar display by relative motion is produced in a short range. Nevertheless it has not been obvious, so we would research how much distortion will be produced by it. And taking this in a broad sense, we can consider that the change of a target's display between each revolution of a scanner is also the distortion. Some photographs are shown here, indicating these distortions described previously. We conclude that about 15 r.p.m. is the minimum speed of a scanner's rotation for the high speed vessel. Because the higher the speed of a vessel and the lower the one of a scanner's rotation, the larger is the distorting tendency.
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k. Namikawa, Y Tarumi
Article type: Article
1960 Volume 23 Pages
33-39
Published: December 25, 1960
Released on J-STAGE: September 26, 2017
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First we drew the contours of the constant probability density of the ship-position every each existent Decca Chain in the Northern European Waters, using the following formulae: P (P, R)=sinφ_P+sinφ_R-sin(φ_P+φ_R) P (P, G)=3/4 {sinφ_P+sinφ_G-sin(φ_P+φ_G)} P (R, G)=3/5 {sinφ_R+sinφ_G-sin(φ_R+φ_G)} [See Fig.2〜Fig.9 in this paper] Secondly, by means of the combination of the above mentioned contours, we made the practical "Decca Navigation Chart" by which we could select the appropriate chain and pair to find out the most accurate Decca Fix at any position in the ditto Waters. [See Fig.10 in this paper]
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T. Hashimoto, M. Nishimura, K. Yamaguchi, k. Isobe
Article type: Article
1960 Volume 23 Pages
41-45
Published: December 25, 1960
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The frequency analysises of the sea noise and sound of fishes are very important to discriminate the species of fish or to forecast the catch of fish in set net fishing. We recorded on the magnetic tape recorder the sounds of yellowtail, squid and porpoise which were received by hydrophone devices or sonobuoy devices. And then, these sounds were analyzed for frequency by means of the Panoramic Sonic Analyzer. We obtained the following conclusions. 1) When the sea was calm, it was indicated that the level of sea noise was higher in the frequency range below 1 kilocycle the upper range. (Fig. 6A, B, C) 2) When the sea was rough, the level of sea noise increased in the whole frequency band and it depended upon the velocity of wind, but we found no change in the frequency distribution. (Fig. 6D) 3) The yellowtail and the squid made some peculiar swimming sound which distributed in the frequency band higher than the sea noise and therefore, we could clearly discriminate the sea noise and the sound of fishes. (Fig. 6E, F)
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T. Hiraiwa
Article type: Article
1960 Volume 23 Pages
47-54
Published: December 25, 1960
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First of all, the writer formulated statistically the trends of abatement of speeds as concerned with different degrees of ship's speeds and wind scales on the basis of the data reported formerly (tables 1, 2, 3), in cases of head wind and waves, side wind and waves, and fair condition. Secondly, he tried to consider the selection of the most efficient and econmoical routes for the San Francisco-Yokohama run and Hawaii-Yokohama run in winter, on the basis of the most frequent wind directions, the mean wind forces, the frequenties of gales (fig.4) and the aforesaid abatement of speed due to those winds and waves. Thereupon, he assumed seven courses for former run and computed the respective times required and rates of delay, and showed the results in figs.6 and 7 ; concerning the latter run, he assumed four courses and showed the times required and delaying rates in table 4 and fig.9.
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k. Yoneda, T. Nohara, M. Okada, H. Kikutani, F. Kawamoto, K. Oikawa
Article type: Article
1960 Volume 23 Pages
55-68
Published: December 25, 1960
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Following the experiments on riding at single anchor which was reported in Part 1. we carried out some experiments on mooring and riding at single anchor with drag anchor. The results of experiments have shown us that the following methods are recommendable to ride her safely in strong wind even when ship is light loaded and trimmed by the stern. 1. If moored with both anchor cables at an angle of about 60°or more, ship's yawing is chekd entirely. 2. If at single anshor, using a drag anchor is effective to minimise ship's yawing so far as the wind is not so strong, that is under 30m/sec. In order to check the yawing, the shorter the scope of drag anchor chain is, the better effect can be attained so long as the anchor drags the bottom.
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I. Tanaka, H. Tani, A. Iwai, Y. Nishiyama
Article type: Article
1960 Volume 23 Pages
69-74
Published: December 25, 1960
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The authors have investigated on the effect of wind pressure as an element of external forces affecting on the transverse stability of ship loaded with Lauan Wood on deck. From our results of wind-tunnel with water tank experiments, the increasing of the heeling moment due to wind pressure have been described as follows ; C_<m_t>=C_<m_0>+m(H/B)^3 where C_<m_t>=the heeling moment coefficient due to wind on ship with deck loading C_<m_0>=the heeling moment coefficient due to wind on ship without deck loading. H=the mean height of spaces of deck loading. B=the breadth of ship. m=Coefficient, depending on the ratio of the mean height of lateral areas above the water line to the ship length.
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Y. Oda
Article type: Article
1960 Volume 23 Pages
75-93
Published: December 25, 1960
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Y. Sasaki
Article type: Article
1960 Volume 23 Pages
95-100
Published: December 25, 1960
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It has been said that handling techniques of ship facing to the cases chiefly depended upon only manueuver's experiences and immediate intuitions, however, experiences referring to handling characteristics of our own ship would be more available. HAYABUSA MARU was No.5 HUKURYU MARU, which had been engaged in tuna longline fishing before converted to the training boat of the Tokyo University of Fisheries, at that time we had not any details concerning to these problems, so we carried out the experiments in December 1959 off Tokyo for the purpose of ascertaining the particulars. Consequently we got some knowledgements, that are presented below.
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T. Okita
Article type: Article
1960 Volume 23 Pages
101-104
Published: December 25, 1960
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F. Ito, G. Miyamoto, S. Osaka, A. Yamaguchi, J. Shibuya, G. Oda, S. Ao ...
Article type: Article
1960 Volume 23 Pages
105-111
Published: December 25, 1960
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Article type: Appendix
1960 Volume 23 Pages
App1-
Published: December 25, 1960
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Article type: Cover
1960 Volume 23 Pages
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Published: December 25, 1960
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Article type: Cover
1960 Volume 23 Pages
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Published: December 25, 1960
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