123 12 5 128 

 Diver-Controlled Jet Cleaning . Hydraulic jet cleaning ' ' has been 



used to remove debris, loose paint, rust, and scale from ship hulls in dry 

 dock and to clean heat exchangers, reaction vessels, and similar equipment. 

 The simplest jet delivers a stream of water at pressures up to 680 atmos- 

 pheres (10,000 psi) at 90 1/min. Jet pressure and volume can be controlled 

 to remove fouling and loosely adherent paint without damaging sound coat- 

 ings. Abrasives can be introduced to increase cleaning effectiveness and 

 rate. Seawater can be used if freshwater is scarce. While effective 



operation of hydraulic jets by free-swimming divers has not been demon- 



125 

 strated, divers standing on a firm surface underwater have cleaned 



concrete structures and pilings. If the jet could be modified with compen- 

 sating thrusters as in Figure 12, operation by free-swimming divers appears 

 feasible. 



Figure 12 - Hydraulic Jet Cleaning Tool 



61 



