X as in expression 1 is the average values of the man-hour that is predicted in case of maintenance personnel is ten or less.

X is calculated as a valuable factor which is effected other causes on the basis of the influence by an installation system. When estimating the man-hour of the equipment, it depends on the system type, the number of the repairers, the kind of ship and the difference of the engine output. Y is an evaluation mark of an influence factor in the physical causes and human causes. The evaluation mark are summed following three mark. The evaluation mark is totaled the mark of maintenance environment, mark of the maintenance support and mark of the personnel ability. K is a compensated coefficient by the factor which has an influence on the man-hour.

X. K and Y of the approximate expression are calculated below based on the statistical data[2, 3].

　

5 MAN-HOUR ESTIMATION

　

5. 1 Introduction from the main factor to the approximate expression

According to the Table-1, in case of the repairer is less than ten, man-hour of all average is 4.17 and standard deviation is 10.68. Hereinafter, it makes average man-hour μ[mh] and it makes a standard deviation of average man-hour σ[mh].

The values of pμ+1 σ in this case became 14.85. About the ten systems on Table-1, logarithm ratio to the all average man-hour is calculated with μ of each system divide by 4. 17. According to the same way, each logarithm ratio to all average man-hour are calculated about the Table 2, 3 and 4 as in each number of repairers, each kind of vessels and each main engine outputs. These results are shown in Table-5.

Thus, X values of the average man-hour for target equipment is shown by the following expression.

X=4.17×exp (Logarithm Ratio for each type of systems

+Logarithm Ratio for each number of repairers

+Logarithm Ratio for each Ship of Classification

+Logarithm Ratio for each Main Engine Output) (2)

　

For example, if carry out the maintenance of a fuel oil purifier by 2 men and it's main engine output 24000 KW, container ship;

X=4.17×exp (0.10 - 0.36 - 0.10 - 0.07) =4.17×exp (-0.43) =2.71 MH/case.

　

5.2 Adjustment by the factor that exerts an influence on man-hour

The evaluation factors for personnel to the artificial influence factor have some steps.

　

　

The evaluation of maintenance circumstances and the evaluation of maintenance support to the physical influence factor have a minimum mark at zero and the best mark at two. It writes down to the following Table 6, 7 and 8. The total maximum of the evaluation mark becomes 95, the minimum values becomes 11 and the average becomes 53. The man-hour of the equipment approximately 90% distributed which is occupied within 15man-hours from the statistical data of the Item 4.1. And this distribution is similarly Logarithmic Normal Distribution. This becomes approximately the values which added average to the standard deviation. When the evaluation mark becomes average, the estimate man-hour X is belonged next range level. The X is one when it's gotten the maximum evaluation mark and X is 15 when it's gotten the minimum evaluation mark. Therefore the estimate values of the man-hour;

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