In the two-cycle diesel engine with constant pressure turbocharging, the deviation of the maximum pressure is observed in each cylinder. It was supposed that one of the reasons is the interference of exhaust pulse to the scavenging.
In this study the dynamic scavenging tests are conducted by using a single cylinder model in order to investigate the influence of exhaust pulse on the scavenging. By comparing the experimental results with theoretical calculation, the effect of exhaust pulse to the scavenging is discussed. The results obtained are as follows: 1) When the exhaust pulse is given during the scavenging period, the scavenging flow is obstructed and the concentration of fresh gas in the cylinder decreases. 2) The influence of exhaust pulse to the scavenging seems to be most serious when the pulse is given at the middle of the scavenging period. 3) By means of the experiment and calculation one of the charac-teristics of the scavenging becomes clear in regard to the interference of exhaust pulse.

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An ultrasonic flaw detection technique has been successfully developed for the purpose of detecting internal flaw of marine propellers. When the technique is applied to an actual propeller, it must be decided what size of flaw is allowable and what area of blade should be detected. In this report, the following analysis and calculation have been developed for these purposes.
(1) Whether fatigue crack will be more progressive from the flaw of propeller blade or not is analyzed by using linear-elastic fracture mechanics and the value of ΔK_th of the propeller material.
(2) The largest allowable dimensions of flaws are calculated at several conditions of stress, blade thickness and aspect ratio.
(3) The stress distribution on the propeller blade in wake flaw is calculated by using unsteady lifting surface theory. The area should be detected flaws is decided from the distribution of critical flaw size for each propeller.

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In relation to the fact that emulsion fuels have a remarkable effect on the reduction of exhaust gas and on saving energy in diesel engine and boiler, the effects of emulsion fuels on soot formation in the combustion of fuel droplets are investigated. The experimental results are summarized as follows:
(1) In the combustion of water/oil emulsion fuels, mini-explosion phenomena are observed. It has the advantage of exposing more fuel to the air, therefore the burning velocity is more rapidly than that of the original fuel.
(2) But the more we add water to the fuel, the more the droplet temperature in combustion goes down and ignition delay increases.
(3) Emulsion fuel-droplets have a remarkable effect on reduction of looting ratio. The swarm of soot particles is smaller in proportion to add water in emulsion fuel.
(4) The size distribution of soot particles and the size of crystallites in a single soot particle are affected by the combustion of the emulsion fuel-droplets.
These experimental results suggest that, in the combustion of emulsion fuels, not only are water in emulsion fuel effective on soot formation by abrupt physical phenomena (mini-explosion), but has influence on chemical reaction.

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Storage batteries which are used as an emergency source of power and are important devices on board vessel. However, the study on co-ordinative protection of distribution circuit supplied from storage batteries is said to be insufficient.
Recently, the number and scope of electronic equipment are increased especially in automation and instrumentation fields and thereof the storage batteries has become more and more essential as an emergency or standby power source. The Electric Committee of MESJ has investigated and studied the matter on various characteristics of storage batteries, magnitude of short circuit current, contribution of rectifier equipment, etc. and also property and combination of protective devices to execute the co-ordinative protection.

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Rising of conductor temperature of cable when running the constant current intermittently is lower than that of cable when running the same constant current continuously, therefore current ratings of cable used for intermittent service is larger than those of cable used for continuous service.
In case of IEC Pub. 92-352, for supplying cable used for such equipments loaded on ship as cargo winches, engine room cranes and similar devices, it is specified that the current ratings in intermittent service shall be those which were increased by applying the correction factor to the continuous current ratings.
Therefore in this paper, we have reported the fundamental consideration of current ratings in intermittent service and also reported the result of the current ratings in intermittent service of EP rubber insulated cable used for ships in JIS C 3410 by applying the calculating method of the current ratings in intermittent service specified in IEC Pub. 92-352.

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The Semi-Submerged Catamaran (SSC) has been expected as a new type of promising marine vehicle to break the various performance limitations imposed by the conventional monohull or the conventional catamaran vessel.
This paper introduces the outline about the characteristics of SSC performance and the design conceptions on her propulsion system in addition to the outline of the commercial prototype of SSC ferry for 446 passengers, which had been completed for the first time in the world at the end of August, 1979 at Chiba Yard of Mitsui Engineering & Shipbuilding Co., Ltd.

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