in order to stress the wire to 20 percent of its ultimate strength. 

 All metal -to -metal contact between the cable specimens and the tension 

 jig is eliminated by means of fiber-reinforced plastic washers and 

 plastic sleeves. 



Four cable-tensioning jigs containing specimens of eight different 

 materials are included in the test program for the first deep-sea tests. 

 The cable materials are as follows: 



Bright plow steel 

 Bright Monitor 

 Galvanized plow steel 

 Electrogalvanized plow steel 

 Type 316 stainless steel 

 PVC over Amgal 

 USS Tenelon 

 Aluminized steel 



Two specimens are mounted in each of the four jigs. The jigs are 

 located on the STU so that each cable specimen crosses the water and 

 sea -floor interface and is partially embedded in the sea floor. 



Stress-corrosion testing of appropriate metallic materials may 

 be conducted by utilizing the method illustrated in Figure 5 and 

 described by Phelps. 5 in this method, the specimen, which is prepared 

 in the form of a strip 1 inch wide and O.O5O inch thickj, is placed 

 in flexure in a rigid jig. The jig holds the ends "J. 000 ± 0,001 inches 

 apart. The tensile stress induced in the outer fibers of the mounted 

 specimen is a function of the length of the specimen; the length is 

 calculated for a desired stress level. In order to assure that there 

 are no bimetallic electrical currents between the metal specimen under 

 test and the metallic jigp an insulating film is placed between the 

 jig and the specimen. To prevent complete loss of a broken or displaced 

 specimen, a hole is drilled throiigh each end of each specimen and a 

 thin plastic cord is used to tie it to the jig. 



Specimen Handling 



The following procedure for treating the specimens which were mounted 

 on the first Submersible Test Unit (see Ocean Environment Experiments) 

 is planned for all deep-ocean exposure tests. 



Following the degreasing, the metallic specimens were handled with 

 clean cotton gloves and immediately placed in sealed canisters which 

 contained silica-gel desiccant. All materials^ both metallic and 

 nonmetallic J, were then taken to a workroom where the himidity was 

 maintained at approximately 20 percent relative humidity. The specimens 



8 



