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Article type: Cover
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Cover1-
Published: March 30, 1973
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Article type: Cover
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Published: March 30, 1973
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Kiyoshi TERAI, Tatsumi KURIOKA, Hideshi TAKEUCHI
Article type: Article
Pages
1-12
Published: March 30, 1973
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In recent years we have advanced various kind of rationalization such as establishment of workshops, improvement of working environments and automation of works, and have gradually achieved the effective work method. The rationalization like these has been started with adoption of assembly of blocks on assembly yard and afterwards, has been developed in the field of assembly of blocks in parallel with the progress of welding technique. Since assembly of blocks made the most contribution toward the rationalization of shipbuilding practice, as mentioned above and will also take a vital role in the future, we consider it necessary to make a systematic study of block assembling method, which will help us develop and improve it. From this point of view, the authors are examining the significance of the block assembling method and the development of production engineering for assembly of blocks, and are quantitatively comparing major assembling methods in terms of production hour, which has a great influence on the production cost.
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Sadaichi MIYATA, Hisayasu URA, Ziro OKAMOTO, Saburo TOMOSADA, Akihiro ...
Article type: Article
Pages
13-16
Published: March 30, 1973
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In view of increasing production by minimizing the construction period on berth, and also, to keep the constant working hours of berth, the most important and necessary for the shipyard is the efficient utilization of the existing berth, and to commence outfitting in the engine room at an early stage of construction is also effective for minimizing the period on berth. From this view-point, we have adopted tandem-construction method. While ship is constructed on the aft portion of berth by the method, aft body blocks of next ship, including engine room, is pre-erected on the fore-portion of the same berth. After launching of the former, the latter is removed to a proper position of the aft-portion of the berth. We had already adopted this method several times intermittently. But, as recently it became necessary for us to adopt this method continuously. We started with this planning from 1971, and completed the first travelling successfully on 12 th Oct., 1972. This method is characteristized by safety control and minimum operators with full auto matization of travelling equipments. In this report, the planning and first travellng result are described.
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Kimio TSUJITA
Article type: Article
Pages
17-24
Published: March 30, 1973
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Various kinds of bridge manoeuvring equipments, with which main diesel engines are controlled automatically from the bridge, have been used in large vessels for about ten years. On the other hand, several super-automated ships have recently come into service and these ships have computers which watch, record and detect various conditions of main diesel engines and auxiliaries. However it has not yet be reported that computers carried out the functions of bridge manoeuvring for a main diesel engine. Ordinary bridge manoeuvring system for a main diesel engine has up to now been of sequential control system, and not system of handling calculations. And we could not find out merits of using a computer. However it is expected that a mini-computer control system will be available for the main diesel engine bridge manoeuvring on super-automated ships in the future, because the reduction of price, rise of ability, rise of reliability and development of utility technique are being extremely accelerated. We tried to apply a mini-computer (HIDIC-100) to HITACHI B & W K-EF type main diesel engine bridge manoeuvring system, i. e. we designed a mini-computer control system for the above engine, made the object program, and carried out tests for performance and sequence of the system with satisfactory results.
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Fumio YAMAMOTO, Takao KAMATA, Hiroshi NAKAKAMURA
Article type: Article
Pages
25-32
Published: March 30, 1973
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A study is performed on the fatigue life of the blade fastening bolt for the large controllable pitch propeller, based on the analysis of stress applied to the bolt and fatigue strength of the materials for the bolts. A full size controllable pitch propeller model was employed in the test to estimate the working stress in the bolts. Forces equivalent to the estimated fluid and centrifugal forces were statically given to the model propeller blade (diameter of hub : 437.5 mm) and its edge respectively. As the strength of the bolt seems to vary in accordance with the fatigue strength of materials and its rigidity, highly anti-corrosive materials such as stainless steel SUS 44 B, and copper alloys AMB 102 F and ABB-2 were employed for the test. Full size bolt head models of the three materials were also tested to estimate fatigue strength under the direct stress condition. Following conclusions are derived from the tests mentioned above. (1) The working load is distributed over the blade fastening bolts in a way quite different from that assumed by the ordinary calculating method. (2) Loads in the front side bolts of the driving face are larger than those of the other bolts. (3) Distributed load of each bolt decreases asymptotically to a certain value as the initial tightening force increases. (4) There exists the optimum combination of the hub diameter, bolt pitch diameter and blade flange thickness to make the working load of each bolt minimum. (5) The SUS 44 B shows the highest fatigue strength while the AMB 102 F and ABB-2 were lower and the lowest, respectively. (6) The optimum tightening force is found with the aid of the working load∼initial tightening force diagram and endurance limit diagram of the bolt.
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Tomoo HANAWA
Article type: Article
Pages
33-42
Published: March 30, 1973
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The present report is concerning a method of designing the hull form of high speed fine ships in the prohibitive speed range of Froude number, 0.28-0.32, where the displacement, the length, the breadth-beam ratio and the metacentric height are given as design requirements. The procedure to be taken is as follows. (1) C_p curve is obtained by analysing its slope curve, comparing actual hull forms with theoretical ones. (2) C_ω curve is drawn based on both C_p curve and the value of the optimum waterplane area. (3) The designed body plan is given by modifying the frame lines of parent ship form numerically and geometrically, with taking account of the above C_p and C_ω curves.
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Hiroshi TAGANO
Article type: Article
Pages
43-52
Published: March 30, 1973
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This paper presents a method to estimate the wavemaking resistance of ships at the preliminary design stage. The effect of prismatic curves on the wavemaking resistance is investigated theoretically. From the investigation, an estimation formula is obtained by combining the theoretical formula of wavemaking resistance and test results of about 100 ship models with statistical analysis. Examples of estimation of wavemaking resistance of a variety of ship forms, e. g. a cargo liner, a general cargo ship and a passenger cargo ship are given. It is shown that the reliability of the formula is sufficient for preliminary design of ships. It is also demonstrated that the formula is very effective for improvement of ship hull forms.
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Taketoshi OKUNO, Yoji HIMENO
Article type: Article
Pages
53-59
Published: March 30, 1973
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In this paper a method of composite expansion in singular perturbation problem is applied to the calculation of the pressure and velocity distributions on ship hulls. An uniformly valid solution of the fluid motion about a ship moving forward steadily is obtained through the matching and combining process between the inner and the outer solutions of asymptotic expansion. The results of the calculation of the surface pressure and the crosssectional sinkage force distribution of a fishing vessel are compared with the inner solution and also with measurments.
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Yoji HIMENO, Ichiro TANAKA
Article type: Article
Pages
61-74
Published: March 30, 1973
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A new integral method for predicting the development of the three-dimensional turbulent boundary layer on ship hull surfaces is presented. The effect of the cross flow on the momentum equations is exactly taken into account so that the integral form of the boundary layer equations is reduced to a set of partial differential equations. The auxiliary equation consists of the moment of momentum integral in the stream-wise direction, where the eddy viscosity is assumed to be a scalar, and a probable form of distribution is derived as an extension of the two-dimensional case. Coles' wall-wake law in three dimensions is used both for the assumption of the velocity profiles and as the skin friction formula. The potential flow outside the boundary layer is calculated using Hess and Smith's method. The results of the boundary layer calculations applied to three ship forms show fairly good agreement with the experiments. Also, it is confirmed that a considerable difference exists between potential and viscous stream lines, and that a vortex-like cross flow occurs near the bilge and the bottom of the fore body with a tendency to decrease as the Reynolds number increases.
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Masaaki GANNO, Matao TKAGI, Ryusuke HOSODA, Haruko SHIMAZAKI
Article type: Article
Pages
75-82
Published: March 30, 1973
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Theoretical calculations are made for the nominal loss of speed due to resistance in waves and for the deliberate loss of speed for the purpose of avoidance of danger. Using these results, the optimum ship route is calculated on the basis of Pontryagin's maximum principle. A few examples of the calculated trajectories and speeds are presented. Also, the propriety of using Pontryagin's maximum principle to calculate the optimum ship route is discussed.
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Yutaka TANAKA, Kuniji KOSE
Article type: Article
Pages
83-90
Published: March 30, 1973
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Full ships, such as supertankers, are generally poor in stability on course. Consequently the first-order linear equation of steering motion is no more accurate to describe steering performance of such ships, though it has so far been used successfully for other variety of ships. There have been a few ideas of improving this by introducing a simple nonlinear term to be added to linear equation proposed by Norrbin, Nomoto and Bech, e. g. Eq. (6) or Eq. (7). Making use of these approximate nonlinear equations of steering motion, the authors propose a procedure of defining the characteristic coefficients of a given ship by analysing the zigzag steering test records by means of the phase plane analysis. According to the results of applying this analysis on the zigzag test of directionally unstable supertankers and models, it is concluded that: (1) The second-order nonlinear equation works well to describe steering motion of unstable ships. (2) Phase plane analysis is proved to be a useful procedure to define the manoeuvrability of a given ship from steering trial, especially in case of unstable ships. (3) The first-order equations of motions do not work well in spite of introducing the nonlinear term, especially at frequent rudder movement.
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[in Japanese]
Article type: Article
Pages
91-94
Published: March 30, 1973
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Article type: Appendix
Pages
95-97
Published: March 30, 1973
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Article type: Appendix
Pages
98-100
Published: March 30, 1973
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Article type: Appendix
Pages
App1-
Published: March 30, 1973
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Article type: Appendix
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Published: March 30, 1973
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Article type: Cover
Pages
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Published: March 30, 1973
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