Visual Observations of Replacement Acoustic String 



The replacement acoustic string was retrieved from Ft. Lauderdale 

 Harbor for inspection after 6 months of exposure. The corrosion behavior 

 of this string was of interest not only because it was to replace the 

 failed acoustic string, but because many of the materials used in the 

 new string were the same as those used in the failed string. Corrosion 

 effects noted on the replacement string could therefore be used to 

 determine which areas of the failed array should be inspected in detail. 



The most severely corroded portions of the replacement string were 

 the Monel 400 bands used to secure the rubber hydrophone boots to the 

 hydrophone cases. Most of the bands were severely corroded due to 

 crevice corrosion at the band- joining buckles. Many of the bands had 

 failed completely. The 90-10 cupro-nickel hydrophone cases were very 

 slightly etched. The electromechanical cable was unattacked. The 

 painted steel portions of the replacement string were unattacked except 

 for areas where the steel was exposed by abrasion. The protective 

 coatings used were essentially intact except where mechanically damaged. 



Visual Observations of Failed Array Upper Buoy 



The upper buoy had been only slightly damaged by being washed' 

 ashore. Nearly all surfaces of the assembly were covered with a thick ■ 

 (1/8-inch to 1/4-inch) accumulation of encrusting coral. Fresh mechanical 

 damage to the structure could be easily identified by the lack of encrusting, 

 coral on the surface at the point of damage. The steel tube support 

 structure was corroded slightly at a few areas of paint failure, particularly 

 on the top sides of the structural members. This could have been due to 

 personnel climbing on the structure prior to deplo3mient. The four steel- 

 buoyancy spheres had a few areas of minor pitting up to 1/8-inch deep. 

 The paint coating, where visible due to the flaking off of the encrusting 

 coral, was reasonably intact and relatively free from blistering, flaking,, 

 or chalking . 



The electromechanical cable termination at the base of the buoy 

 had been previously disassembled and details of its condition upon 

 retrieval were not well documented. However, as for many of the other 

 terminations retrieved and inspected, the minimum diameter of each armor 

 wire was measured upon disassembly and was recorded. This information 

 was used by NSRDC in evaluating the condition of the terminations in an 

 attempt to infer the condition of the terminations which were not 

 recovered. 



* 



In this report all points where the armor wires are 



discontinuous are referred to as terminations, even 



when the termination is used only as an electrical 



conductor breakout. 



