In the previous study, the experiments have been carried out using high viscosity fuels up to 1000 cSt (@50°C) on a medium speed diesel engine and it has been reported that combustion characteristics such as ignition delay and smoke at low load deteriorate according to the increase of viscosity.
Since the fuel used above mentioned experiments has been prepared by the same diluent and base oil with different mixing ratio, it can be said that the different combustion characteristics along with the viscosity is due to the difference of their mixing ratio i.e. the influence of diluent and base oil.
In the actual fuel market, however, fuels are made using various kinds of diluent, and it is supposed that the combustion characteristics will vary owing to the properties of diluent and mixing ratio even on the same viscosity.
This paper describes the results of experiments using the fuel of 180 and 380 cSt (@50°C) prepared by different diluents mixed with vaccume residue as base oil. Pure diluents are also tested in order to compare with high viscosity fuel.
As a result, it is known that fuel quality does not depend on viscosity and diluent acts an important role in the combustion characteristics especially on ignition delay.
Ignition delay correlates well with CCAI, UOP-K and corresponds closely to the mixing ratio as well.
The limit of stable operation due to long ignition delay is also discussed in the paper.

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Recently in the field of marine diesel engine, there is a remarkable trend to increase the Pmax. and the piston stroke in order to get higher effeciency. Therefore the cylinder liner and piston ring condition is getting more and more severe in the viewpoint of temperature, pressure and the exposure of the oil on the sliding surface. In addition, the effect of over cooling on the cylinder liner and the use of sulfur rich fuel have diversified the wear phenomena of rings and liners. With the situations above, it has become more important in the liner lubrication to reduce the wear rate with the minimum comsumption of lubricating oil as possible. In order to solve these problems it is necessary to recognize the various conditions of wear on the liner surfaces.
In this study the replica observation method is investigated to evaluate those conditions in many vessels, and the following results are obtained.
1. Replica wear modes are classified into six patterns - abrasion, adhesion, polish, corrosion, etching and steadite corrosion - according to their characteristic features. They can be grouped into two types in relation to the effect of corrosion.
2. These relative wear rates are clarified in the wear mode diagram taking into account the degrees of mechanical and chemical wear.
3. Since the steadite corrosion seriously affects the liner wear, it is very important to restrain such corrosion to get the minimum wear.
4. The replica observation method is highly effective for judging the liner wear conditions and therefore, it can give us the fundamental approach to improve the liner wear.

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The paper expressed chronologically the development of all technical topics between 1195 and 1945, which are extracted from the historical manuscripts written by the above Sub-Committee regarding to all the electrical and electronic equipments progress in the Japanese warships and merchant vessels before 1945.
As these works have been completed mostly by the relief of The Japan Shipbuilding Industly Foundation, our members express gratitude to the favour.
The electrical and electronic equipments containt as follows:
1) electrical apparatus
2) electrical propulsion
3) radio and others electronic apparatus
4) electrical navigation instruments
5) degaussing equipments of ships etc.

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Because of the importance of the synchronous-condenser (S.C) in the Thyristor-inverter Type Shaft Generator System, the characteristics of this system are examined from the view point of its effects. An expression of S.C is derived from experiments and its accuracy is verified. The results of experiments on the model of the system are
1. With no Automatic-Frequency-Control equipment, it has two conditions, stable and astable, depending on the state of S.C.
2. Both capacity and power factor characteristics of S.C have to be considered when the system is analyzed and designed.

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The exhausted quantity of soots and hydrocarbons from diesel engine have a tendency to increase as the quality of marine fuel oil deteriorates. Their soots are composed by formed soots from gas phase and cenosphere (such as residual carbon), stick to the surface of exhaust gas economizer, and prevent the heat transfer rate for soot diposits. The heat transfer pipe may occur the heavy damage for oxidation of soot deposits (soot fire), and melt for high temperature.
It is important to be the basic researches on soot oxidation of fin surface.
This studies become the principal experiments on the combustion state of soot pellicle on the fin surface, and on the changes in quality of fin surface with combustion.

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