inlet has the more severe requirements for fouling prevention, it can be 

 assumed that results of research and development to solve this problem 

 will solve lesser fouling problems of the OTEC plant. 



ANTIFOULING PROTECTION FOR FIBER-REINFORCED PLASTICS 



The fouling of seawater piping systems is well documented. ' 

 This section addresses antifouling protection for fiber-reinforced plastics 

 utilizing conventional and developmental antifouling coating systems as well 

 as development of inherently antifouling FRP systems. FRP has been proposed 

 for the cold water pipe for the OTEC power plant." The use of FRP for the 

 warm water intake screens of the power plant also is feasible. The recom- 

 mendations for antifouling systems for these two components are based on 



7 8 

 the proposed designs as described in the Lockheed and TRW reports. 



Requirements of antifouling protection for these two components will 



vary. Warm water intake screens will be the photic zone, whereas the 



cold water pipe may not. 



Current Antifouling Coating Systems 



An antifouling coating would appear to be a feasible means of protect- 

 ing an FRP cold water pipe. However, existing antifouling coatings have 

 not been developed specifically for piping systems but rather for pleasure 

 craft and Government and commercial ships. Therefore, application and 

 expected service life of current antifouling coatings must be evaluated 

 for their applicability to FRP pipe. This section only summarizes the 

 matter of antifouling coatings since the subject has already been con- 

 sidered. 



Ideally, the maximum service life of an antifouling coating ranges 

 from 2 to 4 yr,-'-^^ but in practice the service life of conventionally used 

 antifouling coatings is shorter. Navy documentation indicates the anti- 

 fouling effectiveness of copper-oxide-based antifouling coatings ranges 



73 

 from 3 to 18 months in tropical waters to 3 yr in temperate waters. 



A limited study of commercially available organotin paints, which began 



in 1973, indicated that under static panel-exposure tests the antifouling 



service life of organotin paints may range from 2 to 7 months, depending 



41 



