Cavitation erosion may sometimes occur on cylinder liners or cylinder blocks to cause serious troubles to penetrate them. It had been clear that its phenomenon was resulted from the liner vibration by piston slap. So we studied the calculation method of piston slap and transient response of liner and became to be able to estimate the possibility of the generation of cavitation erosion without running engines.
Many researches have been done and many calculation models have been proposed about piston slap. But some are considered to be insufficient or too complicated for industrial use. So we considered the new calculation model — the force of the oil film between piston and liner ruled the movement of piston. And we assumed two separate oil film for the purpose of treating translational and rotational motion.
We guessed that the force added to liner was equal to the reaction force which piston received from liner and got the wave form of force from the acceleration of piston.
We made a FEM model of cylinder liner and cylinder block to calculate the transient response of liner. We added the force to the model, changing its form into equivalent triangle form.
Then we got a good relation between measured and calculated liner vibration.

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The combustion chamber plays an important role in the fuel-air mixing process and resultant fuel spray pattern which have a large influence in a diesel engine. Furthermore, the chamber wall cools off the gas in the combustion chamber and quenches the combustion zone, thus the thermal efficiency and the combustion efficiency of an engine would be lower.
In order to investigate the effect of the combustion chamber shape on the engine performance, the authors conducted some experiments using a single cylinder 4-cycle test engine and a test equipment. Piston crown shape, combustion chamber height, number of fuel nozzle holes, direction of fuel nozzle hole and charge air pressure were chosen as the experimental factors.
From the results, it is confirmed that the fuel mixing process with surrounding gas is mainly done by the mobility of the fuel spray. Therefore, it was concluded that the interference of the chamber wall in the motion of the fuel spray must be avoided especially on the early stage of the spray travel.
Based on the results, then the authors redesigned the piston crown of their 4-cycle medium-speed diesel commercial engine, and confirmed the improvement of the combustion performance.

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In general, the copper suboxide is contained in anti-fouling paint for the ship. It prevents from growing the marine lives on the shell plating in the water because that the ionization of copper suboxide comes out from the surface of painting plates.
An anti-corrosion method that zinc or aluminium plates is fixed to the propeller surface is applied for the marine copper alloy propeller. Marine lives, in this case, seem to be able to grow easily on the surface because that the ionization of copper from the surface is suppressed. But there has been no report about the marine fouling. On the other hand, there are reports that an excessive anti-corrosion current keeps out the marine lives on the surface.
From these reports, effect of these anti-corrosion methods to the marine growth has not been declared.
Therefore, it is investigated, the growth rate of marine lives on two conditions of propeller material, namely the condition that zinc or aluminium was fixed and material itself, in the sea water in Oshima for about one and a half year. The test results in the difference which the formers were covered with marine foulings very much and the laters negligible.

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This paper describes an Adaptive Automatic Steering Control System which has recently been developed by Nippon Kokan K.K. in cooperation with Yokogawa Hokushin Electric Corporation.
The purpose of the system is to optimize both the course-keeping and course-changing ability of ship's autopilots under diverse operational and environmental conditions.
The control systems for course-keeping and course-changing are distinctly different:
(1) Course-Keeping Control
An on-line parameter optimization procedure, based on the Hill-Climbing Method, is used in order to minimize the propulsion losses due to steering.
(2) Course-Changing Control
Model Reference Adaptive Control (MRAC) is used in order to improve the transient characteristics during course changes, which makes it possible to assign the desired characteristics by a reference model.
Full-scale sea trials have been carried out with this system, which show a great advantage for both economical steering ability and improved maneuverability.

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