FOUR-MEMBER DERRICK 



SAFETY 

 HOOK 



Figure 6. Diagram of the Wash- Bore Unit Used. A 15-horsepower engine 

 powers a clutch unit which in turn powers the cathead and 

 water pump. The pump, a double acting piston type, develops 

 over 100 pounds per square inch. A high-pressure hose 

 carries this water to the drill string. The operator uses 

 the mechanical aid of the cathead to raise and lower heavy 

 objects and to operate the hammer. 



