LIFTING AND LOWERING SYSTEMS 



CANDIDATE SYSTEMS 



There are nine primary system configurations given consideration in 

 this study: 



1. Hydrodynamic winch 



2. Platform and pipe 



3. Ship and pipe 



4. Platform and cable 



5. Ship and cable 



6. Free ascent/descent 



7. Winch-down 



8. Ship with buoyant assist 



9. Platform with buoyant assist 



During the course of the analysis some of these basic systems were modified 

 by the addition of a subsystem. In general, however, the nine basic solutions 

 to the problem form the core of the entire report. 



Figure 1 gives an overall view of how the solutions are categorized. 

 Three basic approaches to handling heavy loads at sea were conveniently 

 defined on the basis of the support vessel (s) involved; these are: (1 ) con- 

 ventional surface craft, (2) unconventional surface craft, and (3) surface 

 independent. 



Conventional Surface Craft 



The most frequently proposed heavy-lift systems are those employing 

 either a ship or a self-propelled platform which is used as surface support for 

 suspending the load. Two suspending mediums, pipe and cable, are investi- 

 gated in this report. Hence, there are four possible configurations for the 

 conventional surface craft category: 



1. Ship with cable 



2. Ship with pipe string 



3. Platform with cable 



4. Platform with pipe string 



These systems are illustrated schematically in Figure 2. 



