About 9 months after the relocation of the mooring, another potential 

 profile was made. A new, more easily handled diving boat was used, and there 

 was no appreciable wind. All four ground legs were covered with about 1 foot 

 of mud, and one anode on Leg 4 could not be located. However, it was much 

 easier to measure the potentials that are recorded in Table 12. All the potentials 

 measured were still well above -850 mv, but those on Leg 2 were noticeably 

 lower than those on the other legs. This could be due in part to a sluggishness 

 of the meter and the inability of the diver to maintain contact witH the chain 

 for an extended period of time. One of the anchors was receiving full protec- 

 tion from corrosion, one partial protection, and two no appreciable protection. 

 It is interesting that the anchor on Leg 3 that was receiving full protection after 

 4 months was receiving no protection after 9 months. 



The potential profile of the mooring was again taken 1 5 months after 

 relocation. It was possible to measure the potentials at all key points of the 

 mooring. These measurements are recorded in Table 13. Again all of the 

 measurements were well above the desired minimum of -850 mv. 



This time Leg 1 had very slightly lower readings than the other three 

 legs. Two of the anchors were receiving partial protection from corrosion and 

 two were receiving no appreciable protection. 



Eleven months after relocation of the cathodically protected mooring, 

 the buoy was lifted from the water for the annual inspection specified in 

 BUDOCKS Instruction 1 1 153.4B. At that time the buoy was in excellent 

 condition except for extensive marine borer damage to the lower wooden 

 fender. There was very little corrosion above water (a few pinpoint rust spots) 

 and none below. The riser-chain showed no deterioration, and the paint was 

 still intact. A routine thickness measurement with a pair of calipers revealed 

 no reduction in chain thickness but a slight increase due to the thick paint. 

 Both the buoy and the riser-chain had medium to heavy marine fouling typi- 

 cal of other moorings in the area. Tunicates, barnacles, and green algae were 

 the most typical organisms present. These were removed by high-pressure 

 hosing with seawater before the inspection. 



The square area below the waterline of the buoy, which had been 

 sandblasted to bare steel at the start of the test program in order to give a 

 better indication of the cathodic protection of exposed steel, was covered 

 with fouling organisms and a black film, but it had no pitting or other signs 

 of active corrosion. 



The surfaces of the two anodes in the sea chests in the buoy were 

 covered with a loose, yellowish film, but under this film the zinc metal was 

 bright and irregularly pitted indicating satisfactory performance. More than 

 two-thirds of the original zinc remained on each anode. The diver reported 

 that the anodes on the ground legs were in a similar condition. 



32 



