Figure 2. Test mooring buoy during sandblasting. 



Two sea chests were built into opposite sides of the buoy cone, each 

 to house a cathodic protection unit. The modified buoy was sandblasted to 

 white metal (Figure 2) and coated with the phenolic mastic coating system 

 described in Reference 3. The automatic control heads were bolted to 

 threaded studs located inside the sea chests, and 80-pound magnesium anodes 

 were secured between them and the lower mounting brackets (Figure 3). 

 Nylon spacers were used to isolate the anodes electrically from the buoy; 

 thus, current from the anodes had to pass through the control heads and the 

 connected ground cables before reaching the buoy. Each of the two ground 

 cables was threaded through a series of chain links that were welded to the 

 bottom flange and then was welded to the flange at a point opposite the sea 

 chest from which it came (Figure 4). Immediately before placing the buoy 

 in service, a square-foot section of coating on the underwater portion of the 

 buoy was sandblasted to bare steel (Figure 4), giving an exposed steel specimen 

 on which the effect of cathodic protection could be determined visually. 



