INTRODUCTION 



Field activities of the Naval Facilities Engineering Command 

 (NAVFAC) have encountered considerable difficulty and much expense 

 in maintaining adequate protection from corrosion for buoys and ground 

 tackle used in Fleet moorings. The rates at which the protective coatings 

 deteriorate and the steel corrodes in seawater vary greatly in different loca- 

 tions throughout the Naval Shore Establishment because of differences in 

 temperature, nature of environment, and type of service rendered. It has 

 been stated that ". . . in certain far eastern water the average effective dura- 

 bility of a steel navigational buoy is only about eight years, and that even 

 in this short life repairs to the underwater shell are required every third to 

 fifth year."'' Thus, a large portion of the buoy deterioration occurs where 

 the structure is continually immersed; this is the only area where cathodic 

 protection from corrosion can be effective. The purchase and maintenance 

 costs of mooring chains are several times those required for mooring buoys. 

 As a consequence, the Naval Civil Engineering Laboratory (NCEL) was asked 

 to investigate the use of cathodic protection for protecting both the sub- 

 merged portion of mooring buoys and the ground tackle used to secure them 

 in place. 



BACKGROUND 



In 1964, when the present work was initiated, approximately 

 100 Fleet moorings were maintained by U.S. Navy Public Works Center, 

 San Diego. The value of a typical mooring (a Mark 1 1 peg-top buoy with 

 a riser-chain and four ground legs) was estimated to be $33,500, of which 

 $2,000 was for the buoy and $31 ,400 was for the ground tackle. The 

 estimated annual maintenance cost for each mooring was $1 ,600, most of 

 which was for the ground tackle. 



BUDOCKS Instruction 11153.4B of 9 April 1965 calls for (1) annual 

 inspection of mooring buoys for damage, deterioration of corrosion, and 

 physical condition of the ground tackle connected to the buoy, (2) lifting 

 of bouys from the water every 3 years for painting and required repairs, 



