SCOPE OF STUDY 



The main body of the report is subdivided into five principal sections. 

 The first three sections contain a discussion of nine candidate load lifting/ 

 lowering systems, and form the bulk of the report due to the accessibility of 

 the raw data and experience record. Both load ranges, 20 to 100 tons and 

 400 to 600 tons, are given consideration. Mission profiles and systems 

 descriptions are included and, where pertinent, appendixes are referenced. 

 A relatively simple systems effectiveness model has been used herein as an aid 

 in optimizing the choice(s) for the most feasible system(s). The model is 

 described, the relevant operational parameters are discussed in detail, and 

 the results of the model presented in tabular form. 



Load positioning and guidance is considered separately from the task 

 of lowering very heavy loads to the sea floor. The fourth section of the 

 report is addressed to this problem. Unlike the previous case for lifting and 

 lowering systems, however, no formal systems modeling was attempted due 

 to the paucity and uncertainty of the available data. 



The DOT TOP suggests that a Near Bottom Transport Subsystem 

 (NBTS) would prove to be a useful auxiliary to a surface-supported, heavy- 

 lift system. Thus the fifth and final section of the report attempts to define 

 an NBTS mission profile as well as conceptualizing and comparing several 

 candidate NBTS vehicles. 



MISSION PROFILE 



If one were to speculate on the mission profile for the first generation 

 of large underwater systems, it seems logical to suppose that most units 

 would be self-contained and require only one lift. The Manned Underwater 

 Station designed by General Dynamics or a nuclear reactor are examples of 

 loads which possess this self-contained characteristic. 



The mission profile may best be described if the goals of the project 

 are stated : 



1 . Transport an underwater structure of up to 600 tons from a port 

 to a specified location at sea. 



2. Place the underwater unit on the sea floor. 



3. If necessary, monitor, control, and service the unit. 



