JETTING-IN BASE PIPE SECTIONS 



Divers attach 1 2- inch fire hose to the top of the base 

 pipe, using a bell reducer to fit the larger diameter of the 

 pipe. Communication is maintained between divers and the 

 support boat by a signal line. On signal, the crewmen 

 start the high-pressure water pump, which forces 60 gal- 

 lons of water per minute through the welded nozzle of the 

 pipe at 100 psi. The water pressure displaces the sedi- 

 ments and allows the pipe to settle under its own weight into 

 the sea floor (fig. 5). After the downward movement of the 

 holding sleeve is arrested by the two T- screws and the bell 

 reducer reaches the top of the sleeve, the diver diverts the 

 water by means of a Y-gate valve located between the fire 

 hose and the bell reducer, and signals the support boat to 

 stop the pump. At this point the pipe has settled 4-g- feet 

 into the bottom, the fins are covered, and the jetting- in is 

 completed. Approximately 90 seconds is required to jet in 

 one base section. 



The fire hose is disconnected and the tripod and 

 leveling device are lifted over the protruding pipe section. 

 The tripod is relocated at the next position. An air-filled 

 lifting bag attached to the tripod during relocation facilitates 

 movement by the divers. 



13 



