BACKGROUND 



The first stages of the investigation included a comprehensive 

 assessment of currently operating heavy-lift systems in the light of the TDP 

 requirements. Nearly 20 past, present, and planned lifting/lowering systems 

 were given careful consideration.'* 



It is clear that firms engaged in underwater construction and related 

 fields expect no extreme departures from conventional methods of lowering 

 loads into the ocean within the TDP time frame or even beyond. A good 

 example of what is planned is the Alcoa Seaprobe, an all aluminum vessel 

 which will be capable of lowering, via pipe string, loads of up to 200 tons 

 to 6,000 feet — perhaps by 1972.^ The Glomar Challenger, a recently 

 developed and constructed ship, will lower loads of at least 200 tons to 

 unspecified depths in the very near future.^ 



Since industry-related development is based on extensions of past 

 experiences, the tendency of the task team was to follow similar lines of 

 thinking. It was assumed at the outset of the project, and subsequently 

 affirmed, that most of the investigative effort should be concentrated on 

 assessing the possibilities of extending the more tradition-based systems to 

 meet the design criteria. However, sufficient time and study were given to 

 the more novel solutions to adequately specify their respective problem 

 areas and assets. Always kept in mind was the limited potential for more 

 than nominal hardware development if the TDP schedule was to be met. 

 Consequently, any technological potentialities were carefully considered to 

 assure that only realistic predictions of future developments were utilized in 

 the cost/effectiveness evaluations. 



It can be seen that any one of the candidate systems previously dis- 

 cussed is actually a synthesis of component elements common to other 

 systems. For example, cable is a component of the ship/cable, platform/cable, 

 and hydrodynamic winch lift systems. The feasibility of these systems is 

 primarily dependent on the feasibility of using cable. Similarly, adding 

 buoyancy to the cable systems (buoyant assist) or to the loads in the free 

 ascent/descent concept (buoyed load), produce systems which basically 

 possess the same degree of feasibility; that is, the problems of one are the 

 problems of the other. While there are differences among the systems, they 

 will be accounted for in a more refined analysis; at present the concern is 

 only with "basic feasibilities." Thus, the relative feasibilities of a large 

 number of possible system configurations can be adequately determined by 

 carefully specifying the limits and attributes of their common components. 



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