Journal of Zosen Kiokai

Wave-Making Resistance in Shallow Sea and in Restricted Water, with Special Reference to its Discontinuities

Takao INUI

1954 Volume 1954 Issue 76 Pages 1-10
Published: 1954
Released on J-STAGE: July 23, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.1

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In this paper the author points out theoretically some discontinuous characteristics of wave resistance in a shallow sea and in a restricted water. The main results obtained are as follows :
1) In a shallow sea with finite depth and infinite width, the resistance itself is continuous all over the range of travelling velocity, but its first derivative with velocity is discontinuous at the critical speed or the solitary wave velocity.
2) In a restricted water whose depth and width are finite simultaneously, the resistance itself is discontinuous at the critical speed.
From this, the general conclusion may be drawn that the more parts of restriction the water has, the higher degree of discontinuity appears itself onto the wave resistance.

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Some Methods of Simplified Solutions of the Problems about the Ship Propulsion

Kaname Taniguchi

1954 Volume 1954 Issue 76 Pages 11-18
Published: 1954
Released on J-STAGE: January 20, 2010

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.11

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In this paper the Author reports about the methods of simplified solutions for the following problems, which are often proposed in the propulsion of ships :
1. Simplified method of determining the diameter of propellers.
2. Relations of the small changes of resistance, speed, revolution and propeller.
2. Variation of power due to the small change of ship-speed.

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The Electric Method to Prevent Corrosion of Screw Propeller made of Iron or Steel

Katsumi Okuda, Nobuo Tagawa, Torakichi Hara

1954 Volume 1954 Issue 76 Pages 19-29
Published: 1954
Released on J-STAGE: July 23, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.19

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For the purpose of preventing corrosion of screw propeller made of cast steel or cast iron, we propose the following method ; the cathode of any D. C. source prepared in the ship is connected to a propulsion shaft bearing, and its anode to a mild steel plate attached outside the hull, so as to produce electric current through the sea water from the anode plate to the screw propeller. We cleared the theory of this method by means of fundamental experiments about electrolytic corrosion of mild steel, and established a designing course for the practical application.
At the practicalizing tests of this method by 2 ton wooden built motor-boat for about one year, and by 430 ton steel vessel for about six months, satisfactory results were obtained in either case even with rather weak current, that is, 0.14 A for the former and 5 A for the latter.

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Mathematical Considerations on the Electric Method to Prevent Corrosion

Hikoshiro Sakai

1954 Volume 1954 Issue 76 Pages 31-67
Published: 1954
Released on J-STAGE: July 23, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.31

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It is generally known that most of metallic corrosion in the solution of salt is wholly an electrochemical phenomenon. As, in case of electrochemical corrosion, the quantity of metallic corrosion should be proportional to the electric quantity which flow from the face of metal towards a solution, the question of corrosion is really a question of electric current, and it is a phenomenon not to be considered without the geometrical conditions of shape, size, etc. of metal. Hence, it is natural that the law of similarity should prevail at model experiments. The object of this treatise is to show how the geometrical conditions of shape, size, etc. affect the metallic corrosion, by applying mathematics to the question. However, in connection with this matter, there remain many problems of which this is only a part.

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On the Vibration of Plane Structure

Yoshiyuki Yamamoto

1954 Volume 1954 Issue 76 Pages 69-83
Published: 1954
Released on J-STAGE: July 23, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.69

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In this paper, the author proposes a new method to solve the vibration problems of plane structure, and discusses the lateral vibration of ship by means of it. It is a sort of extension of the slope-deflection method in vibration, and is applicable only to the structures each member of which is straight and has uniform section. Since most of the actual structures may be considered to have such a property, this method is sufficient for the practical purposes. And vibration problems of complicated structure may be easily solved.
Vibration of the stsucture considered here is described by eleven functions α, β, γ, δ A, B, C, D, P, Q and R, the properties of which are similar to those of hyperbolic and circular functions and are tabulated in table A 1.

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Suggestive design of nails

Masamichi Harada

1954 Volume 1954 Issue 76 Pages 85-98
Published: 1954
Released on J-STAGE: July 23, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.85

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If we connect two lapping timbers by nails and apply them a load which acts on nails as the shearing force, the apparent slip between two timbers is proportional to the load. But naturally there is a limit of proportion on the relation of slip and load, and if the load goes over the limit, the slip becomes gradually remarkable.
By our experimental investigation, we found that the relation of slip and load has a proportional limit, when the maximum bearing pressure about nail-holes attaines the proportional limit of bearing of timbers. Then we may propose a principle of design of connection by nails as following procedure.
At first we must obtain the proportional limit of bearing of the timbers by the material test, then we assume most suitable safety-factor and decide an allowable bearing pressure; - this safety-factor may be nearlly equal to the unit and be more or less than the unit.
Secondly, making the maximum bearing pressure equals to the allowable bearing pressure, we can calculate, the safe loads for nails; - wher the maximum bearing pressure is connected with the safe loads by a theory of elasticity.

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[title in Japanese]

[in Japanese]

1954 Volume 1954 Issue 76 Pages 99-106
Published: 1954
Released on J-STAGE: July 23, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.99

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On the Bracketless System of the Bottom Longitudinals

Masao Yoshiki, Junichi Asano

1954 Volume 1954 Issue 76 Pages 107-117
Published: 1954
Released on J-STAGE: January 20, 2010

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.107

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In this paper we deal with the strength of the doubling liners applied to the bracketless system of the longitudinals proposed by Isherwood, when the liners are bent by the action of longitudinals which resists the external pressure. In the Isherwood's paper, the doubling liners were considered only from the viewpoint of the continuity of the longitudinal strength of ship at the bracketless ends of longitudinals. As the results of our calculation, the bending stress at the doubling plates reaches greater value than the longitudinals, so that it is necessary to decide the scantling of the doublings more carefully considering the bending action together with the longitudinal strength.

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On the Strength of Corrugated Steel Plate

Y. Fushimi

1954 Volume 1954 Issue 76 Pages 119-136
Published: 1954
Released on J-STAGE: July 23, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.119

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The shell & bulkheads of ships in general are made of flat plates which are reinforced by vertical & horizontal stiffeners, and these stiffeners are connected by large quantity of angles, face plates and brackets, for which a great number of labours are required.
The new construction which is called “Corrugated Plates Construction” is consisted of corrugated plates which have stiffness themselves and remarkably decreased stiffeners instead of flat plates and numerous stiffeners.
In this construction, we can reduce a great number of steel members and labours, and accordingly build ships, simpler in construction, lighter in weight and more reduced in price than that of flat plate construction.
The author has tried an experiment entitled “Strength of Corrugated Steel Plates ” to acquire the standards & data for applying this corrugated plate to practical shipbuilding.
This work deals with the instruction of the experimental model, its method and comparison of actually measured values with the approximately calculated values in regard to deflection of model plate.
As the result, we have known that there is not so difference in applying Beam Theory to the corrugated plates.
In this construction, it is proved, that the weight is reduced by 30% in comparison with the flat plate construction as required by rule.

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[title in Japanese]

[in Japanese], [in Japanese]

1954 Volume 1954 Issue 76 Pages 137-146
Published: 1954
Released on J-STAGE: July 23, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.137

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On the Engines of Standard Cargo Ships after the War

Saburo Senoo

1954 Volume 1954 Issue 76 Pages 147-165
Published: 1954
Released on J-STAGE: July 23, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.147

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As the standard cargo ship after the war, selecting three kinds of vessels ; 6, 000 tons gross for the ocean liner, 3, 000 tons gross for near sea and 1, 000 tons gross for the coaster, the author studied the economical propelling machinery for each of them, under the present circumstances of Japan. Adopting the water tube boiler and the steam turbine and elevating properly the steam pressure and temperature, we can reduce the fuel consumption about 16% and machinery weight about 1930% as compared with the hitherto generally adopted practice of the cylindrical boiler and the steam turbine or the cylindrical boiler and reciprocating engine, and initial costs are not different. Moreover the author recommends electrification of the auxiliary machineries. To stick to the cylindrical boiler and the reciprocating engine on account of its safety even to-day, is the same idea to use the paper lamp instead of the electric lamp to-day. Such prejudice should be also corrected that the steam turbine is inferior to the reciprocating engine in maneuvering property as the astern power of the former is less than that of the latter.
As reference the author described the diesel engine plan for 6, 000 tons ocean liner.

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On a Reciprocating Steam Engine without Steam Valve

Shigemasa Yamane

1954 Volume 1954 Issue 76 Pages 167-172
Published: 1954
Released on J-STAGE: July 23, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.167

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This engine is equipped with a steam valve st the steam port side of H. P. cylinder of the triple expansion reciprocating steam engine, abolishing the steam receivers between the H. P. and I.P., also the I.P. and L. P. cylinders. These cylinders are connected with the steam pipe, and the pistons work instead of slide valves for suppling and exhausting the steam. Then the steam shall be successively expanded from the H. P. to L. P. cylinder. Thereby, the pressure drop which happens by the steam receivers is prevented and converted into the mechanical work done.
In brief, it is the merits of this steam engine to get a simple mechanism, decrease of steam consumption, increase of mechanical efficiency, diminution of troubles, and reduction of weight and cost of production.

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On the Restricted-Water Effect on Ship Resistance

Masao Kinoshita

1954 Volume 1954 Issue 76 Pages 173-213
Published: 1954
Released on J-STAGE: January 20, 2010

DOIhttps://doi.org/10.2534/jjasnaoe1903.1954.173

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