1. The submerged weight of the system should be less than 40 kips 

 to permit use of the NCEL-developed motion-compensating winch. 



2. The power required for pile installation should be less than 

 100 horsepower. 



3. The system should require less than two hours of on-bottom 

 time to emplace the minimum number of piles. The time limit includes 

 system checkout, leveling, etc. 



4. The system should be able to emplace piles in a wide range of 

 seafloor types; i. e., soft to stiff cohesive soils and loose to dense 

 cohesionless soils. 



5. The system should be capable of expansion in size (plan 

 dimensions of structure) and number of piles. 



6. All components should be within the state-of-the-art; i.e., 

 minimum development required. 



7. The system should utilize a minimxim of mechanical operations 

 and control functions. 



8. The system should be handled by a single ship or a single tug- 

 barge combination. Required deck space is a function of the plan 

 dimensions of the installation, but the minimum space is approximately 

 12 ft X 12 ft for the emplacement system, 4 ft x 8 ft for a control 

 van, 10 ft X 10 ft for a crane, and 10 ft x 20 ft for winches, prime 

 mover, and miscellaneous equipment. The vessel must have a 20-ton 

 crane to place the system overboard. 



Table I summarizes the operating requirements. 



Common Design Characteristics 



A schematic representation of a seafloor pile emplacement system 

 is shown in Figure 1. The system comprises five subsystems: 



1. The foundation/anchorage subsystem, which includes a template, 

 piles and connections. 



2. The installation subsystem, which includes the emplacement 

 mechanism (i.e., vibratory drivers, or jack-in or screw-in mechanisms) 

 and associated power conversion and distribution equipment (i.e., 

 hydraulic pumps, lines, valves, reservoir, gears, etc.). 



3. The electrical subsystem, which includes submerged electric 

 motors, transformers, electrical cable, and generator. 



