Quantitative Estimation of Factors Influencing Maintenance on Damaged Propulsive Shaftings

We have analyzed statistically on damage data of propulsive shaftings for the classed ships with Japanese flags by means of application of quantification theory. Then the effect of factors on the maintenance of propulsive shaftings has been studied quantitatively. As the result it has been found that the amount of maintenance in water lubricated type has a tendency to become larger than that in oil lubricated type. That is to say, the former is much affected by ship's age showing time-dependent trend while the latter is time-independent and is affected by other factors such as propeller revolution, coupling type of shaft, rather than ship's age. And also some examinations have been made by using Fault Tree analysis and Fuzzy concept.