from submerged surfaces. These data have been the stock in trade of the 

 various groups that design and construct marine equipments and structures. 

 For effective utilization in the design of an OTEC plant, there exists a 

 requirement for a single comprehensive survey of all this information. 

 The information in many cases is well documented; its incorporation during 

 design phases should be straightforward. However, several significant gaps 

 exist in our present knowledge. Some deficiencies have to do with scale- 

 up of presently used techniques. These areas will be identified, and it is 

 suggested that the information provided be used only as a guide until hard 

 experimental data are available. 



SCOPE 



This survey covers two basic areas: the deterioration of materials 

 and the control of biofouling. The primary interest in the former is the 

 performance of concrete, low-alloy steels, and fiber-reinforced plastics, 

 and the use of anticorrosion coatings to protect steel and special alloys. 

 Emphasis in the latter area is on the nature of fouling, suggested anti- 

 fouling coatings for all types of surfaces, inherently antifouling materials 

 of construction, and fouling removal techniques. 



MATERIALS OF CONSTRUCTION 



CONCRETE 



Concrete has been proposed for construction of the OTEC power plant 



7 8 



platform.' The platform could be deployed on the surface of the ocean or 



submerged several hundred feet with an access tower penetrating the surface 



of the ocean. The platform provides a structure on which to secure the 



power modules and the cold seawater pipe, to provide storage facilities, 



and to house operating personnel and auxiliary equipment in a dry 



1-atmosphere environment. The cold seawater pipe, as large as 130 ft in 



diameter, transports large volumes of cold seawater drawn from as mush as 



4000 ft deep. The warm seawater ducting is an integral part of the upper 



portion of the platform. ^ 



