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Article type: Cover
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Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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Article type: Cover
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Published: September 30, 1974
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[in Japanese]
Article type: Article
Pages
1-
Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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Masaaki KUROI, Matao TAKAGI, Ryusuke HOSODA, Momoyo TAKAHASHI
Article type: Article
Pages
3-10
Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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Simulation of navigation in the North Pacific in winter is made using a calculation method of optimum ship route which is based on Pontryagin's maximum principle. The result is compared with the experiences of the high speed single screw container ships in PSW (Pacific South West) route. It is shown that the calculation simulates well the experiences of the ships.
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Shoichi NAKAMURA, Kimio SAITO, Tetsuro IKEBUCHI, Masaaki KUROI
Article type: Article
Pages
11-23
Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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In the design of a ship it is very important to estimate the maximum responses over the life of the ship on a given sea. For this purpose the long-term statistical predictions by an electronic computer have been developed to give the long-term probabilities of the ship responses exceeding a particular level value. The procedure of this calculation involves three steps: (1) ship responses in regular waves by the Ordinary Strip Method (2) short-term statistical values of the ship responses in irregular seas by means of the linear superposition principle (3) long-term statistical values of the ship responses using the long-term statistical wave data on a given sea In this report the authors have attempted to extend this procedure to calculate the long-term distribution considering the effect of ship operation defined by the speed drop and course change in rough seas. Numerical results by this method on the North Pacific Ocean are compared with those by the usual method and it is shown that the effect of ship operation is considerably large.
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Minoru MORI, Motoaki YANASE
Article type: Article
Pages
25-34
Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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One of the setbacks to increased production in shipbuilding is the painting process. The reason is simply because the painting process requires drying time which precludes other works. In our attempts to shorten the drying time, we studied the following possibilities that may lead to the development of fast-drying paints and painting techniques as well as painting machines that answer this purpose. (1) We manufactured quick-drying paints by mixing recently developed high reaction rate hardners (isocyanate, carbamine, amine and polysulfide) and resins (epoxy, coal tar and polyester). (2) The pot life of these paints is very short, so much so that we manufactured experimental plural component plastics spraying equipment. (3) We clarified the relationship between painting conditions and paint film quality and the relationship between the spraying equipment mixing performance and film appearance. As a result of the study, it has now become possible to shorten the drying time to about 1/10 (1∼4 hours) and reduce the painting frequency by half (1 coating) in the painting process of vessels.
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Hiroto KOTERA, Shoichi OHTANI, Yasuo ARAI
Article type: Article
Pages
35-40
Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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A Doppler Speed Log utilizing the Doppler effect of under-water ultrasonic waves has been developed by the authors as an alternative of the existing speed measuring instrument, i. e. pressure log or electro-magnetic log. It has following superior characteristics. (1) To be able to indicate ship's speed against water or ground. (2) To have high accuracy throughout speed range. (3) To have no protrusion from bottom so that it can be used in shallow water or in harbours with floating obstructions. (4) To be low cost compared with Doppler Sonar. It is confirmed that the Doppler Speed Log has sufficient accuracy, reliability etc. after testing on a bulk carrier. In this paper, effect of transducer installation error on accuracy of measurement, frequency of ultraronic weves to be applied, reliability of instrument etc. are discussed.
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Hiromasa TAMAI, Hirofumi ONIKI
Article type: Article
Pages
41-50
Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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With a receot demand for increase in ship size and speed, multi screw-twin or triple-has been adopted in many cases of fine ships such as container ships and car ferries. In a single screw fine hull form where good course stability and turning ability can be obtained by installing a suitable size of rudder, we have not given so much importance to the matter of manoeuvrability. In a multi screw fine hull form, we are allowed to select the number and shape of rudders which have much effect on maneuvrability, especially course stability, while it is necessary to design the around-rudder-part not to cause reduction in propulsive performance without unnecessary rise-up in building cost. We, Kawasaki Heavy Industries, Ltd., built and are building high speed car ferries and high speed container ships equipped with twin screw. In the former ships, to develop high manoeuvrability, twin rudder was installed taking account of their speciality of frequent operation in port. In the latter case, in designing the container ship treated in this paper, whether to select single rudder or twin rudder was raised as an important problem for study because of its different function from the former's. This container ship is now placed on the New York line. (Capacity: 2,068 of 20 feet containers Engine: 2 sets of 40,000 BHP engine Service speed: 26 knots) To obtain a solution of the problem, we conducted, at an initial design stage of the ship, a manoeuvring model test at our Kakogawa Exprimental Basin with full load condition. From an analysis of the model test result and expected surrounding conditions of the ship in its operation, we decided to adopt a single rudder and built a twin screw container ship with a single rudder. Its sea trial result was satisfactory, and it is favourably rcceived by crews as a ship of good manoeuvrability. In this paper, we state the result of the said model test carried out in process of deciding the stern arrangement including the number of rudders and the rudder area of the ship, and also that of the actual ship test conducted after delivery.
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Hiroyuki SADAKANE, Motohiro HINENO
Article type: Article
Pages
51-58
Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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The non-linear rolling, especially the jump phenomena and its motion from a stationary mode of rolling, is still one of the problems to be sufficiently studied. A navipendular was made to study this non-linear phenomena. Experiments on symmetric rolling of a cylindrical model was carried out on the navipendular. The present report describes mainly stationary rollings after and before jump. It is confirmed that even the rolling with a very large amplitude can be sufficiently assumed to be harmonic and the jump is caused by disturbances such as a sudden change of wave height. It is also shown that the energy balance is held through the change of the phase difference between the rolling and the waves even for the heavy rolling after a jump from the light rolling.
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Takao INUI, Shozaburo OHKOSHI, Hisashi KAJITANI, Shozo KUZUMI
Article type: Article
Pages
59-67
Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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Effective measurements of the three-dimensional flow velocity components around 2m small models are investigated where a specially developed mini five-hole spherical pitot tube of 6mm diameter is applied. The study indicates that: On the measuring devices; (1) The adoption of force-balanced pressure transducer is quite essential which enables the 'time-constant' short and transforms low level pressure movements faithfully. (2) The equipment to calibrate and traverse the pitot-tube should be so designed that actual measurements may be followed right away after calibration tests without removal of any part of this equipment. On the accuracy obtained; (3) Errors associated with measurements are both small in flow direction and in flow component (Figs. 2.4, 2.5). (4) The free surface effect on Vx and Vz cannot be ignored while the same effect on Vy is negligible (Fig. 3.1).
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Masatoshi BESSHO, Masahiko KOMATSU
Article type: Article
Pages
69-76
Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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Hydrodynamical forces acting on a flat plate oscillating on water surface are computed and compared with the former results. The computation covers very high frequency range and could be compared with the asymptotic expansion. On the other hand, there are many useful formulas between various forces with regard to Kotchin's function in such problem, so that they are presented and checked by direct computation. Besides, the existence of solution of the integral equation of this boundary value problem is discussed and the equivalent variational method is presented. An example of its usefullness is also shown.
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Mitsuya YONETANI, Takao ASAI, Shojiro SHIODA, Kazuo UMEZAKI, Tetsuya Y ...
Article type: Article
Pages
77-81
Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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Authors performed various kinds of onboard experiments concerning the hull strength of a very large container ship. Following results were obtained by the experiment. 1) Short term distribution of wave-induced longitudinal stress on the upper deck follows Rayleigh's distribution. 2) Longitudinal bending moment in irregular waves can be estimated by the calculation for regular waves using the significant wave length and height. 3) Stress on the upper deck caused by warping can not be neglected. 4) Athwartship motion of containers in the hold is not always induced by rolling only. 5) Authors' calculation method for hydrodynamic pressure can be applicable to actual ships, but, in this case, wave spectrum should be estimated as accurately as possible.
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Yukio UEDA, Masakatu MATSUISHI, Yutaka YAMAUCHI, Masako TANAKA
Article type: Article
Pages
83-92
Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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The finite element method has been applied to analyses of both structural and non-structural problems. The formulation of non-linear analysis of plates by the method has been already established. However, various difficulties of numerical calculations arises from the large size of equation. The finite strip method was proposed to reduce the size of equations. The usefulness of the method have been reported in the field of linear and buckling analyses. In the paper, the authors applied the finite strip method to geometrically and materially non-linear analyses of plates. The accuracy and convergence of the solution by the method was examined. The results was quite satisfactory and verified the usefulness of the method.
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Hiroo OKADA, Ken-ichi KITAURA, Yoshio FUKUMOTO
Article type: Article
Pages
93-100
Published: September 30, 1974
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In this paper, the behaviour of simply supported rectangular plates under increasing edge thrust and constant hydraulic pressure is experimentally investigated. To verify the theoretical analysis that the authors had already reported, a series of buckling tests, varying systematically the magnitude of hydraulic pressure, was performed with rectangular plates of aspect ratio α=2. The following became known from this experiment: (1) It was recognized in this experiment that according to the magnitude of hydraulic pressure there existed three such typical deformation patterns for these plates as pointed out by the theoretical calculations, and the tendency of the experimental results can be explained well by the calculated values based on the theoretical analysis. (2) In the curves which show the relation between the edge thrust and the deflection, the experimental results agree well with the theoretical results except the case where the behaviour of a plate is dominated by plastic deformation.
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Yoshiteru SAKAI, Katsuyuki TOMIYOSHI, Yoshihiko SAKAGUCHI
Article type: Article
Pages
101-106
Published: September 30, 1974
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In a multi-shaft ship with a large output, it is necessary to take account of the influence of vibration of the bossing on the shafting. We showed in the previous paper the calculating method of the natural frequency of the bossing by the use of the transfer matrix. In an actual ship, thereafter, vibration tests were carried out to investigate the dynamic behaviour of the bossing from an aspect of the vibration and the results were compared with those of calculations. As a result, it has been found that the natural frequency of the bossing can be estimated with a considerable high accuracy by the transfer matrix method.
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Kouhei MATSUMOTO, Hiroaki KADOH, Tamio KOZONO
Article type: Article
Pages
107-116
Published: September 30, 1974
Released on J-STAGE: March 30, 2018
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This paper discusses some problems on the exiciting force of springing vibration. The results obtained from this study are as follows. (1) Experiments by ship models were carried out to confirm phenomena of springing vibration. From the tests, ship hull vibration caused by waves is found to occur when the natural frequency of the model coincides with the harmonics of the encountered wave frequency. (2) An equation of motion of the simplified model for springing vibration is derived in order to explain the mechanism of ship hull vibration due to waves. Two forces, buoyant force and virtual mass force, are derived theoretically as the exiciting force of the springing vibration. But it is found that the virtual mass force reduces to a half of that derived by Watanabe, and the motion exhibits non-linear characteristics because of the existence of time dependent term in the governing equation of motion. (3) Forces of the springing vibration are calculated taking into account the sub-surface effect for rectangular, triangular and circular cross-sections. Results of calculation show that this effect is remarkable for the higher harmonics of the bouyant force. (4) A numerical calculation method of the exiciting force for arbitrary ship sections and wave forms is presented. From the results of calculation by this method, it is shown that not only shape of ship's cross-section but also wave form are closely related to the generation of several components of the exiciting force with the higher harmonics of the encounter wave frequency.
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Article type: Appendix
Pages
117-119
Published: September 30, 1974
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Article type: Appendix
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App1-
Published: September 30, 1974
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Article type: Appendix
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Published: September 30, 1974
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Article type: Appendix
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Published: September 30, 1974
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Article type: Cover
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Published: September 30, 1974
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