handling frame and equipment housing. The kelly drive is essentially a 

 large gearwheel with a square central hole through which the pile passes. 

 The gearwheel is driven at its perimeter by the hydraulic motor through 

 a speed reduction system. The degree of speed reduction required depends 

 upon the specific hydraulic motor chosen and upon the design stalling 

 torque/speed, but ranges from about 20:1 to 60:1. The ten-inch square 

 central hole will be lined with a low-friction polymeric material to aid 

 the longitudinal motion of the piles. 



The hydraulic system is designed as a pressure-compensated, closed- 

 loop oil hydraulic system, similar to the hydraulic design for the NCEL 

 seafloor deep corer.-^ The reservoir is designed to contain the hydraulic 

 valves and pump and the electric pump motor in addition to the hydraulic 

 fluid. A fixed-displacement gear pump delivers a flow of 40 gallons per 

 minute at a maximum pressure of approximately 1600 pounds per square 

 inch. The hydraulic piping required is nominal one-inch I.D. steel 

 tubing with a wall thickness of 0.134 inch. The piping will be supported 

 and protected by the radial members of the handling frame. The system 

 is designed to operate with only four valves that will require surface 

 control — a bypass valve and function valves controlling the three 

 motors. The location of the valves within the hydraulic reservoir mini- 

 mizes the amount of electrical wiring and number of electrical penetrators 

 exposed to the ocean environment. Three internal-gear hydraulic motors 

 are used to rotate the kelly drives. Assuming a speed reduction of 20:1 

 the motors must develop approximately 750 foot-pounds of torque at 200 

 RPM. A single-acting hydraulic cylinder or rotary actuator will be used 

 to trigger the release mechanism that detaches the installation unit 

 from the template. A simplified hydraulic circuit diagram is shown in 

 Figure 11. 



The handling frame is the permanent base for the installation sub- 

 system components and is the intermediate member through which the load 

 of the emplacement system is transferred to the cable. The major loading 

 condition is the shear load through the frame-to-template connectors as 

 the system is being lowered to the seafloor. Although the static load 

 per connector is only about 6.7 kips, the likelihood of dynamic loading 

 during lowering requires that the connectors be designed to resist about 

 40 kips each. 



Electrical Subsystem 



The electrical subsystem includes the electric motor driving the 

 hydraulic pump, the surface and submerged transformers, the electric 

 transmission portion of the electro-mechanical (E-M) cable, and the 

 generator unit. The entire subsystem is similar to the corresponding 

 design for the seafloor deep corer. In fact, the generator unit, sur- 

 face transformer, and E-M cable for the corer could be utilized directly, 

 provided that the subsurface electrical components and the control sub- 

 system are designed to be compatible with the existing hardware. 



17 



