The rails would provide the diver with grips when he is using the single 

 unit jet. When cleaning is complete, the divers leave the water inlet 

 after all their equipment is removed. 



The cleaning of the warm water inlet on the TRW module would proceed 

 in the same fashion except that the vertical hinged screen would be lifted 

 by detachable inflatable buoys. 



It is not clear whether divers could gain access to the interior of 

 the warm and cold water exhausts of the TRW module because of size limita- 

 tions. If they could gain access, they would probably be limited to using 

 a single rotary brush which is too slow and tedious a process. It may be 

 necessary to use an automatic remote control device which is positioned 

 by divers described previously to clean these ducts. These and other con- 

 necting ducts may be too small to clean with multibrush vehicles or 

 other semiautomatic devices. They will have to be cleaned by hand-held 

 equipment . 



Impact on Cleaned Surfaces . Diver brush cleaning can remove fouling with- 

 out damaging anticorrosive or antifouling paint systems. Light fouling, 



slimes, greases, and incipient calcareous forms can be removed by polypro- 



121 

 pylene brushes without damage to paint. Steel brushes are required to 



remove heavy fouling, including mature barnacles and tunicates. Skilled 



divers can clean painted surfaces with steel brushes without damaging the 



paint film. 



Frequency of Cleaning . Cleaning frequency is determined by the maximum 

 amount of fouling not detrimental to plant operation. This can be deter- 

 mined by overall weight increase of the structure and its attendant 



decrease in reserve buoyancy, and by additional factors such as the rate 



131 

 of refouling which usually accelerates after hull cleaning. 



Anchoring Cable . The OTEC anchoring cable is deployed far below critical 

 fouling depths. If fouling removal is required after extended exposure, 



automated methods would have to be devised. It may be feasible to use an 



1 32 

 automated underwater cable system based on an adaptation of Drisko's 



surface preparation and recoating device for guy cables. 



64 



