The fouling of the exterior structure (Lockheed concept) containing 

 the crew living quarters will require that the area between the intersec- 

 tion of the screen and a height of 15 ft be cleaned. No technical prob- 

 lems are anticipated. The methods for mechanical defouling of designated 

 surfaces of the OTEC plant will be derived from the state-of-the-art 

 waterborne maintenance procedures for ship hulls. The primary method of 

 cleaning will entail the use of multibrush vehicles, directly or remotely 

 controlled by divers and augmented by hand-operated rotary scrubbers for 

 less accessible areas. Although not fully developed as tools for use by 

 free-swimming divers, jet devices appear to be suitable in cleaning 

 interior surfaces of the warm water inlet, especially at sharp angles and 

 corners. Prior to discussion of state-of-the-art tools and their modifi- 

 cation for OTEC application it is necessary to delineate the role and 

 limitations of the diver and to explore the possible use of a modified 

 tethered submersible. 



Diver Versus Submersible 



Advantages of diver cleaning include: 



1. Diver-operated cleaning tools are available. 



2. Before and after cleaning, the diver can inspect and photograph 

 the condition of the surface at close quarters. 



3. Diver mobility permits access into relatively confined areas. 



4. The diver can select from a variety of tools to clean specific 

 surfaces. 



Disadvantages of diver cleaning include: 



1. Diver is limited by physical constraints of the environment: 



a. Divers cannot work in currents over 3 knots. 



b. Low temperatures limit bottom time. 



2. Depth and the necessity to decompress limit his work time. 

 Advantages of the tethered submersible include: 



1. Isolates man from the environment. 



2. Eliminates decompression. 



3. Increases the underwater working period. 



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