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Article type: Cover
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Published: March 30, 1984
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Article type: Index
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Article type: Appendix
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Kimio YOKOTA, Sango TOKUNAGA, Norihide WAKITA, Kenji KOBAYASHI
Article type: Article
Pages
1-15
Published: March 30, 1984
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Recently unmanned submergence vehicle ststems have been playing an important role in ocean exploration and the objects of them have been extended to a deep sea more and more. Vehicles in these systems are operated by the remote control on surface support ships and in most cases an umbilical cable is used for signal transmitting and electric power supply. This cable must be long enough to reach the deep sea. This brings about various problems, and particulary two of them are serious ; One is the increase in the signal transmitting loss which results in getting information of less quality from the deep sea and the other is the increase in restriction on vehicle's motion. To solve these problems, we have developed deep unmanned submergence vehicle system of the launcher type with optical communication links. We have developed the primary umbillical cable and the secondary tether cable as an electro-optical complexed cable for deep sea use, and assembled a prototype system consisting of a launcher, vehicle and surface control units. Furthermore, we have carried out the offshore tests by the total system to confirm the utility of it under actual conditions in the sea and have confirmed the system's performance satisfactory.
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Michimasa ENDO, Takehiko KUROKAWA, Eiji MIYOSHI, Tatsuo MIYAJIMA, Hiro ...
Article type: Article
Pages
17-29
Published: March 30, 1984
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Oil-filled and pressure compensated transistor inverter, which is suitable to be installed on 6,000m class deep submersibles, is being developed, in order to get characteristics of small size, light weight and high efficiency. As the first step of developing this inverter, principal parts as mentioned below which are able to function in the environment of high pressure are just developed and reported in this paper. 1) Large capacity power transistor 260 V, 300A 2) Large capacity electrolytic condenser 160 VAC, 6,800 μF 3) Power diode 260 V, 300A 4) Oil condenser 250 VDC, 1 μF and 115 VAC, 147μF 5) Current transformer, reactor, small capacity diode, and resistor All parts developed are manufactured as trial, and examined under three states of (1) atmospheric pressure in air regarding electrical performances, (2) different pressures up to 938kgf/cm^2 in oil regarding electrical and mechanical performances and (3) cyclic pressure of 1,000 cycles from 0 to 625kgf/cm^2 in oil to prove mainly mechanical durability. As the result of these developments, almost all the parts necessary to assemble the oil-filled inverter system have been obtained, except control circuit which is planned to be installed in pressure proof vessel because of its complexity of being oil-filled and its less capacity. At Present, development of oil-filled and pressure compensated transistor inverter system is in progress as the second step, using the parts developed here.
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Koichiro MATSUMOTO, Takahito KITAGAWA
Article type: Article
Pages
31-39
Published: March 30, 1984
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This paper presents a wind tunnel test procedure on offshore structures and some examples of test results on a model of semisubmersible oil drilling rig compared with calculated values by ABS (American Bureau Shipping) Rules. A model is placed in a water tank filled with water and high viscous fluid on the surface to protect water from scattering due to high speed wind and aid in heel changes. So the tests in relatively high speed wind at any model conditions requested by NMD (Norwegian Maritime Directorate) Rules can be easily realized.
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Norihiro MATSUMOTO
Article type: Article
Pages
41-51
Published: March 30, 1984
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Interference effect coefficients between a hull, a propeller and a rudder were newly proposed, which were arranged together with ship particulars, so they can be estimated without model tests and easily treated in a program for numerical simulation of maneuvering motion. This prediction method was applied for some kinds of model ships in full load condition and ballast load condition, and predicted values of maneuvering motions were compared with the results of free running model tests. Predicted maneuvering motions themselves, propeller thrust and rudder force under maneuvering motions were coincident with those measured values under free running model tests. In the latter half of this paper, a method of scale effect correction for the coefficients of the hydrodynamic mathematical model was proposed. Results of maneuvering trial for full scale ships were compared with predicted results for those, and it became evident that the predicted results were rather similar to the others. Consequently, the prediction method with the interference effect coefficients becomes evident as actually usefull.
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Isao TAKANASHI, Kiyoshi NEMA, Ryuji SAKATA
Article type: Article
Pages
53-60
Published: March 30, 1984
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Ordinary Strip Method (O.S.M.) is used to estmate motion and acceleration of a ship. But, for a shallow draft ship, the calculation accuracy by O.S.M. gets worse on rolling and transverse acceleration especially in short waves. This inaccuracy is mainly due to the inaccurate calulation of diffraction component of roll exciting moment. The authers present the following simplified calculation method of shallow draft ship motion. a) Diffraction forces are calculated by Strict Strip Method (S.S.M.) or Salvesen-Tuck-Faltinsen Method (S.T.F.M.), b) where hydrodynamic coefficients and diffraction forces are calculated by using rectangular form approximation, c) and Froude Krylov force is calculated strictly. This practical calculation method based on Rectangular Region Method (Ijima's method) has a short CPU time and good agreement with model test results and calculation results by close-fit S.T.F.M.
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Masahiro MATSUI
Article type: Article
Pages
61-68
Published: March 30, 1984
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In using the ASMB method ; a kind of method for optimization of ship hull forms, it is necessary to select some suitable data ships. In this report, orthogonal mode functions were intoroduced, and a criterion for selecting data ships was obtained. Four prismatic curves of data ships include parent ship were decided. And there was shown how to optimize a ship hull form using tables based on these ships' the normalized wave analisis data of these ships.
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Yasuyuki TODA, Ichiro TANAKA, Hiroshi SUGIOKA, Hideo MORI
Article type: Article
Pages
69-79
Published: March 30, 1984
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The distorsion of three-dimensional boudary layer around the, so-to-speak, Deep Wigley model due to propeller suction is investigated experimentally by means of velocity distribution measurements ahead of and at the propeller location. It is again found, as was in the previous report, that the difference between velocity distribution with and without propeller is approximately expressed by the change of boundary layer integral parameters. The prediction of propeller suction effect on the boundary layer velocity distribution is made theoretically by use of an integral method and its simplified method. The agreement between the measured and predicted velocities is comparatively good. The effective velocity distribution is also predicted from the nominal velocity distribution.
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Masamitsu ITO, Shosaburo YAMASAKI, Masamitsu OKU, Hajime KOIZUKA, Masa ...
Article type: Article
Pages
81-91
Published: March 30, 1984
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The hydrodynamical component of CPP blade spindle torque that plays an important role in CPP design is investigated. The hydrodynamical blade spindle torque of two model propellers (MP.B 82-1 and 82-2) was measured by the newly developed support-pillar type blade dynamometer in circulating water channels. Measurements for two propellers in the uniform flow field indicated that the maximum value of hydrodynamical blade spindle torque occured at the maximum reverse pitch setting and near the bollard condition (J=0) and the dominant factor influenced on the hydrodynamical blade spindle torque was blade contour. Fluctuations of the hydrodynamical blade spindle torque of MP. B 82-1 in the simulated non-uniform flow field with the wire mesh were measured. Although means are much different, fluctuations were nearly same for the pitch setting angle from-10 to 10 degree. It is also seen that the means in the non-uniform flow fields were a little higher than the values in the uniform flow at the same operating condition (same thrust condition). Comparisons of calculated values by the lifting surface method and measured values at the design and the maximum reverse pitch setting conditions were made and they showed good agreements. Then in order to use at the early design stage, spindle to torque estimating charts of AU-CP series CPP were drawn based on the lifting surface calculations.
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Ryosuke FUJINO
Article type: Article
Pages
93-101
Published: March 30, 1984
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Many ships have become to equip a new diesel engine, which has logs stroke and a lesser number of cylinders. Some of the ships have experienced vibration troubles due to the longitudinal vibration of the engine. The new engine causes large torque variation in the shafting which can generate variation of the angular at the propeller position. The propeller thrust variation due to the angular variation can be generated. The thrust excites the engine longitudinally as well as the longitudinal force of the engine crank. In this paper, the calculation method of the additional propeller hydyodynamic forces due to the shaft vibration is presented, which is based on the unsteady lifting surface theory. The full-scale vibration measurements have been carried out. The calculations of the hydrodynamic forces have been done for the MAU series propellers, too. The calculated results are very related to the reduced frequency. The calculated results has been examined indirectly by the experiments of shaft exciting forces due to the non-uniformity of the flow. The calculated thrust agrees well with the full-scale measurement result.
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Ichiro TANAKA, Toshio SUZUKI, Yoji HIMENO, Tetsuo TAKAHEI, Tatsuo TSUD ...
Article type: Article
Pages
103-120
Published: March 30, 1984
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The scale effect on the wake distribution of a full form ship model is studied experimentally and theoretically on a geosim series of a tanker (the lengths are 12m, 7m, 4.7m and 3.5m). Wake as well as boundary layer velocity distributions are measured by 5 hole Pitot tubes at several stations for each model in towing tanks. The result of measurements is compared with the theoretical results by three existing methods for predicting scale effects of the wake and boundary layer. The most important results obtained are 1) the width of the wake becomes narrower as the dimensions of the model increase, 2) the value of the wake fraction becomes smaller in the wake-peak regions, such as in the neighborhood of the center plane of the model and in the plateau-like zone, as the dimensions of the model increase, and 3) thus, the prediction methods which consider the scale effect in velocity defect as well as in wake width are superior to the one which does not consider the scale effect in velocity defect.
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Matao TAKAGI, Kimio SAITO, Hiroshi OKUBO, Toshio HIRASHIMA
Article type: Article
Pages
121-127
Published: March 30, 1984
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In the 4th paper, the sway inotions of a two-dimensional body with a fender type nonlinear mooring system in waves was discussed and a difference between two calculation methods of C.C. and C.I. was found when the sway motions close to the natural frequency of a moored body occur. The numerical results were compared with experimental values and the validity of C.I. method was revealed. In this paper, the same comparisons are made for a rope and/or chain type nonlinear mooring system and the following differences betw the results of C.I. and C.C. methods are found in the following cases. ・When the floating body which is initially at rest with a loosen rope and/or chain starts its motion (i.e. in a transient stage under the action of wave forces). ・When the subharmonic sway motions appear. By comparing the numerical results with experimental values, the validity of C.I. method is discussed.
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Matao TAKAGI, Kimio SAITO, Minoru SAITO
Article type: Article
Pages
129-140
Published: March 30, 1984
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In this paper, the calculation method of the memory effect functions which is mentioned in the 1st report for Lewis form sections is extended to solve the problem for more complicated shapes. As was shown in the 1st report, the memory effect functions are expressed by the integration of the damping force coefficients or wave amplitude ratios from zero to an infinite frequency. The wave amplitude ratios for all frequencies are obtained by connecting the exact values of the wave amplitude ratios in a medium frequency range with the asymptotic values in a high frequency range. The exact hydrodynamic coefficients as we11 as the wave amplitude ratios for an arbitrany shape are calculated by the method of conformal mapping developed by Takagi. The transformation coefficients are determined by using the Fourier expantion method which is similar to the one used for a wing section of the aeroplane. The asymptotic values of the wave amplitude ratios in a high frequency range are given by solving the high frequency boundary value problem. The method presented here is the extention of the Ursell's for forced heaving circular cylinder. Numerical calculations of the memory effect functions are carried out for the inclined ship sections.
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[in Japanese]
Article type: Article
Pages
141-144
Published: March 30, 1984
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[in Japanese]
Article type: Article
Pages
145-148
Published: March 30, 1984
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[in Japanese]
Article type: Article
Pages
149-171
Published: March 30, 1984
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Article type: Appendix
Pages
173-174
Published: March 30, 1984
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Article type: Appendix
Pages
175-180
Published: March 30, 1984
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Article type: Appendix
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Published: March 30, 1984
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Article type: Appendix
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Published: March 30, 1984
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Article type: Appendix
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Published: March 30, 1984
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Article type: Appendix
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Published: March 30, 1984
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Article type: Appendix
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Published: March 30, 1984
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Article type: Appendix
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Published: March 30, 1984
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Article type: Appendix
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Article type: Cover
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Published: March 30, 1984
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Article type: Cover
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