Journal of Zosen Kiokai

Theoretical Analysis of the Rolling of a Ship with Negative-GM

Y. Watanabe

1928 Volume 1928 Issue 43 Pages 9-73
Published: October 15, 1928
Released on J-STAGE: September 04, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1928.43_9

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Assuniing the stability curve of third degree, the author investigates the rolling of a ship with negative-GM. At first, he studies the free rolling, giving some modifications to Prof. Scribanti's formula and some approximate formulae. Next he analyses the rolling among waves without wind and then accompanied by wind. Therefrom the following conclusions are deduced :
1. The rolling of an ordinary ship with negative-GM among usual waves is quite safe, as there occurs no possibility of synchronism when accompanied by wind, the rolling increases considerably, but is not very dangerous, if sufficient cares are taken on her free-board, and he gives the approximate formula for the maximum rolling angle in that case, which may afford some means to determine the free-board of such a ship.
2. A ship, especially under medium size, with the usually adopted value of positive-GM is very liable to get into a dangerously heavy rolling, which corresponds to synchronism in simple harmonic rolling, but takes place on the waves with shorter period.
Consequently, he recommends the adoptation of small or negative GM, provided with sufficient free-board, for comparatively small-sized full cargo ships, as is generaly believed.

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On the Nature of Ships' Bottom Paints

S. Oshima

1928 Volume 1928 Issue 43 Pages 75-80
Published: October 15, 1928
Released on J-STAGE: September 04, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1928.43_75

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The object of the work was to improve antifouling paints effectively and durably. Among the materials included in the tests were a series of antifouling compositions containing various percentages of toxic materials, and of paints having different colours and bad smells. According to the research made by the writer, it has been found that excellent results were obtained by using plastic paints containing toxic compounds. Some of these paints remained in the salt water free from barnacles and grasses for two years. The upper layer of the slimy film is chalking off gradually, and barnacles and grasses attaching on it fall down with it by scaling of the film of plastic paints.

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APPLICATION OF PULVERIZED FUEL FOR MARINE BOILERS

Yasushi Taji

1928 Volume 1928 Issue 43 Pages 85-100
Published: October 15, 1928
Released on J-STAGE: September 04, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1928.43_85

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General remarks are given regarding the flame length, burners and the safety of pulverized fuel burning. The relative advantage of the unit and central system are discussed. Various designs including the Gasified Fuel system, Clarke, Chapman's system, Brand system, installation on the “Mercer” etc. are described. A certain critisism of various pulverized fuel burning systems and the author's personal desires are expressed.

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On the Turbine Accident of the Japan China Express Liner

T. Muto

1928 Volume 1928 Issue 43 Pages 101-118
Published: October 15, 1928
Released on J-STAGE: September 04, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1928.43_101

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The S. S. “Shanghai Maru” “Nagasaki Maru” sister ships for the Japan China express liner, built by William Denny Bros. & Ltd. in 1922, and propelled by similar sets of Parsons geared turbines.
The blade accident of the low pressure turbine happened frequently on both steamers in past two years, and conditions of the accident seems to be same, but the cause of accidents is unknown.
The author describes on this paper, general observations and special investigations on the cause of the blade accident, concluding with his own opinion from the stand point of a practical engineer and gives some suggestions to designers and persons concerned.

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On the Failure of the Gearing of M.S. “Nagasaki-Maru” and her Manoeuver

E. Utsumi

1928 Volume 1928 Issue 43 Pages 119-138
Published: October 15, 1928
Released on J-STAGE: September 04, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1928.43_119

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The auther had been once on her board before the accident in order to research the vibration of the engine and the hull, on the request of her chief engineer, who was very anxious about the extraordinary noise of the gear, which soon after broke down.
The cause of this failure is discussed in this paper according to the data obtained from the injured part and on the said voyage. It may be remarkable thing that vibration of the case cover of the damaged gear was some orders of the revolution of the H. P. pinion, and in the service sea speed there always occured severe torsional oscillation of third degree, whose frequency also coincided with the revolution of the H. P. pinion, whose teeth seemed to have broken off firstly.
The allowable maximum speed in this injured condition was calculated elaborately by plotting many curves. The test result very nearly coincided with it.
In the appendix is shown a new simple method to calculate the torsional oscillation of the many branched geared turbine system. In this method the effect of the mass of shafting on the high degree frequency may be easily found by using a, nomogram, which was drawn by the auther's many days contrivance.

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On the Fullagar Diesel Engine

E. Yoshida

1928 Volume 1928 Issue 43 Pages 139-194
Published: October 15, 1928
Released on J-STAGE: September 04, 2009

DOIhttps://doi.org/10.2534/jjasnaoe1903.1928.43_139

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The paper treats, about the Fullagar Diesel engines, installed on the motor ships “Florida Maru” and “Cuba Maru, ” and the contents are as followings.
1. General remarks.
2. Principal data and description of the M. S. “Florida Maru” and “Cuba Maru”.
3. Description of Fullager Diesel engine.
4. Principal data and construction of Fullager Diesel engine installed on the M.S. “Florida Maru” and “Cuba Maru.”
5. Results of shop and sea trials of the engine.
6. On the service of the M. S. “Florida Maru” and “Cuba Maru, ” with actual records of services.
7. Engine troubles and their remedies, -cracks of cylinder liners, -crack of crosshead, -fire in scavenge air belt, -carbonization of fuel valves, -crack of pistons.

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