specifications and cliaracteristics were considered. As described, tine resulting 

 systems are more schematic than actual. While errors of omission are unavoid- 

 able, it should be understood that the performance characteristics imposed 

 on the designers are fairly gross and that detailed design is out of the 

 question. It is suspected that during the development program additional 

 requirements will be imposed on the project which will be minor, but still 

 contribute to increasing costs. As the length of the development program 

 increases and related development is carried on in other fields, minor 

 improvements become more opportune. As a consequence, and other things 

 being equal, it appears that the cost estimates are relatively accurate where 

 the magnitude of the required technological advance is small. Where the 

 magnitude of the technological advance still to be achieved is great, a 

 considerable amount of potential variability should be associated with the 

 cost estimate. Of the high-development, little-background type of projects, 

 the experience of industry has been to grossly understate the magnitude of 

 anticipated costs. 



The cost estimates used in this study are; (1 ) the initial procurement- 

 construction cost and (2) the estimated daily operating costs. It is assumed 

 that the respective lifetimes of the systems are roughly the same. The 

 construction-procurement cost is, of course, of interest in any study; the 

 recurring operating cost is included to provide a crude but revealing measure- 

 ment of the size of the operating budget which might be necessary during a 

 system's lifetime. 



Systems Descriptions 



A system representative of each major category is used in the 

 effectiveness analysis. These systems possess what appear to be the best 

 combinations of the critical design characteristics. They are specified in 

 enough detail to permit valid and important distinctions to be made between 

 the competing concepts. Table 6 presents the systems capable of 100-ton 

 lifts. Systems with a 600-ton capacity are presented in Table 7. 



Results and Conclusions 



Table 8 summarizes the results of the effectiveness evaluation. The 

 average score for each system for each figure of merit is given. Table 9 

 presents the composite scores of each system. It should be noted that two 

 systems with scores of the same order of magnitude are considered to be 

 essentially equal in overall effectiveness; only very wide differences among 

 the scores are significant. 



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