Owing to investigate the scavenging process of the loop scavenging two-cycle Diesel engine, some simplified scavenge tests have been proposed and reported. In their papers the relation between the results of simplified tests and characteristics of engine performance have been directly discussed. However, the mutual relation among those results, scavenge flow and gas exchange is not clear, hence we have difficulty of interpretation about the results of simplified tests.
Therefore, we made an attempt to investigate the relation among some simplified tests, scavenge flow and scavenging efficiencies. The results obtained are as follows; 1) The effect of the piston movement in the pattern of scavenging pictures does not appear. That is, if the shapes and arrangements of scavenge ports are same, same scavenging pictures are obtained in the both cases of steady flow and dynamic scavenging. 2) Comparing the two unsatisfactory scavenging pictures which depend on the scavenge port arrangement, it was found that good scavenge could not expected in case of the scavenging pictures of middle tongue rather than that of wall tongues. 3) The part of relation between the results of simplified tests and scavenging efficiencies was cleared by setting up criteria in scavenging pictures.

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In the former paper, we discussed the characteristics of the optimal maintenance policies, that is, Policy I and Policy II proposed by R. Barlow and L. Hunter through the numerical analysis.
In this case, as a failure distribution, we adopted the Weibull distribution, where the shape parameter β was limited to be greater than one. Because in general, the mechanical systems have the characteristics that failure rate is increasing with operating time. It became clear that the new results obtained were very useful for choosing the optimal maintenance policy and for determining the optimal maintenance interval.
In this paper, more we introduce the relations between the availability and the maintenance cost per unit time and then give the procedure of obtaining the optimal policy, the optimal maintenance interval and the maintenance cost per unit time. We illustrate the numerical examples by using the field data on marine maintenance in order to show the usefulness of the procedure obtained newly.

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This device can process sewage and washing water (about 150 liters) of fifty persons per day by thermal resolution-burning system. After the device has vaporized the sewage, it can burn resolved gas and carbonized matter produced and can stinklessly burn without smoke the sewage.
The device has durability, high performance and fitness on board and can be conformable with the provision of “International convention for the prevention of pollution from ships, 1973”.

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The Super Economical Shaft Generator (SSG) System has been developed to offer the most rational features to realize economical ship operation. The SSG System permits the most effective recovery of waste heat when it is incorporated with a marine diesel propulsion plant.
In the System, a turbo-generator is coupled mechanically to the main engine (s) and, when the turbine output exceeds the onboard electricity demand, the excess power is diverted to the main engine to assist propulsion. When the conditions are reversed, the turbo-generator is backed up by the main engine to meet the electricity demand and diesel generators are not required to be operated during ship's normal seagoing.
The System may be employed in combination with low-speed or medium-speed main diesel engines in a wide range of engine output.
Main features of the SSG System are as follows;
1) Unique reciprocal power transmission between the main engine and the turbo-generator set.
2) High power-transmitting efficiency ensured through mechanical coupling.
3) Combined advantages of turbo-generator system and shaft generator system
4) Applicable over wide range of main engine load
5) Utilization of boiler steam for propulsion during the tanker's inert gas topping-up operation
6) Direct conversion of saved steam and electricity to assist propulsion power
7) Simple and most compact design
8) Easy to control
This paper reports the basic design and running data of the first SSG system installed in an 80, 000 MTDW tanker, and also presents an outline of the newly developed SSG MK-II system which enables recovery of low temperature waste heat.

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