On the stern tube bearing of ships that has comparatively wide length and also has overhang weight on an end, bearing load is partial to an end due to lean of the shaft. Therefore, the load condition of this kind of bearing is harsh more than the bearing for general machinery. This becomes especially a big problem with an increase in the size and power rate of ships.
Thereupon, the authors have made experimental study utilizing a bearing test stand with a bearing diameter of 200 mm to obtain the various characteristics of the bearing of this system and especially the friction characteristics and seizure conditions at the low speed of shaft.
The following results are obtained from experimental study:
1) The friction characteristics at extremely low speed range, at shaft starting, etc. and other various characteristics have been obtained.
2) The border between hydrodynamic lubrication and boundary lubrication has been clarified, and, further, an empirical formula for the frictional coefficient of boundary lubrication has been obtained.
3) A clue of estimating the seizure conditions of the partially loaded bearing has been obtained.

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The recent trend towards higher out put on marine diesel engines is remarkable. So, the components of the combustion chamber have been exposed to sever conditions. Therefore, it can be said that one of the most important problem in designing of a marine diesel engine is the strength designing of the components of the combustion chamber. The fundamental problem in this subject is how to clear the stress level and how to estimate the amount of allowable stress on these components.
We mention in this paper the development of the piston crown for our KZ52/90N and the investigation for the problem of our KZ70/ 120E cylinder cover as examples, and also our view point at present regarding the strength designing of the components of the combustion chamber.

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