Recently, sterntube bearings made of heat stabilized asbestos yarn reinforced cresylic resin are used instead of white metal bearings. The authors have studied experimentally on the performance of friction, wear and resilience of this bearing compared with one of white metal bearing. The results are as follows.
(1) This material has high friction coefficient and high wear rate, but no seizure occurred even under no oil supplied condition owing to its oil impregnated fibers.
(2) The Young's modulus of this material is smaller than that of white metal by 1/30. Therefore its Hertzian contact area under inclined journal bearing condition is wider than one of white metal bearing by 5 times, and maximum contact stress of this bearing is smaller than one of white metal bearing by 1/10.
(3) The specific wear rate is 3.65 × 10^-10mm² /kg. When this bearing is applied to the actual sterntube bearing, it is estimated that the wear life of this bearing is about 8 years.
(4) As this material has a rough surface (50-60 μm), the shaft roughness has no great influence upon the bearing performance. Therefore, super finishing of the shaft is not necessary.

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This paper discusses a reliability analysis on the casualties occurred by machinery failures in ship operation. The approach was to conduct a data analysis of failures on marine equipments to evaluate the difficulty of ship operation by the occurrence rate and the logistic delay time due to troubles. The total number of ships to be investigated was 1029 (vessel × year) and the observation period of investigation was twelve years.
The main findings of the study are as follows:
a. Casualties were remarkably increasing in number from in 1970 and showed a peak value in 1972. The occurrence rate of casualty in 1970's was almost twice of that in 1960's. However, the adoption of reduced ship speed operation after oil crisis have made a result in lower failure rate and delay time.
b. The preponderance of the casualties was connected with failures of main propulsive machineries especially main diesel engines. The cause of diesel engine failures was originated from the tendency of high power rate per unit volume of engines.
c. From the statistics at present time, 54% of detection was done by the senses of human being and 46% of detection was done by the mechanical means such as temperature, pressure and level sensor, to find out an abnormal state of a plant that leads to ship stop casualty. And only 11% of decision making was done by mechanical means to judge engine stop operation.

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The vibrations of propeller shaft and the forces exerted on the bearing are investigated.
The theoretical investigation treats the lateral vibrations of shaft system that has many bearings including flexibly supported bearings. The elasticity of shaft, mass of shaft, innertia moment of propeller, bearing characteristics and bearing support flexibilities are considered. Bearing characteristics for inclined journal are calculated on the assumption of short bearing and half-Sommerfeld condition. For the system has many bearings, the calculation of equilibrium state needs iteration. Transfer matrix method is applied to calculate shaft amplitudes and bearing force amplitudes.
Experimental apparatus is made to simulate the propeller shaft system. It is composed of disk, shaft, journal bearings, etc. Electric magnets are used to excite the shaft system. Shaft amplitudes and bearing force amplitudes are measured.
Theoretical predictions of shaft amplitudes and bearing force amplitudes show good agreement with experimental measurements.

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This report is intended for presenting information of lubricating oil system for motor ships especially to the marine engineers who are engaged in the initial planning of machinery.
Though, in general, the design of lubricating oil system, including relevant auxiliary machinery, is peculiar to kind and type of main engine and shipyard, we have gathered information through questionnaire from various shipowners and shipbuilders about 2-cycle and 4-cycle main diesel engines for merchant ships, and on its basis, we have prepared this report.

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