The intervening water mass between the bottom and surface will be considered 

 primarily as an environment for mooring cables and small suspended structures 

 such as underwater buoys and arrays o 



In order to appreciate the potential effects of the deep-sea en- 

 vironment and the necesssity for evaluating materials while exposed to 

 it, the following example of physical data describing the actual en- 

 vironment as measured at the bottom in the Romanche Deep of the Atlantic 

 Ocean, is presented; 



Depth = 25,000 feet 



Ambient pressure =• 11,000 psi 



Temperature - lA5° C 



Salinity = 3^»T5 0/00 



Oxygen - 5^1 ml/L 



PH - 7.7 



Currents - probably on the order of 0,1 knot or less 



While these are the conditions which prevail at this depth, it 

 must be remembered that anything being placed on the bottom must pass 

 through the upper portions of the sea where strong currents, wave action, 

 sunlight, relatively high oxygen content, and a very active biological 

 environment prevail. In addition to these factors, the object being 

 lowered would go through a pressure gradient ranging from atmospheric 

 pressure at the surface to many thousands of psi hydrostatic pressiore at 

 the bottom. 



Factors contributing to changes in and/or the deterioration of 

 materials exposed to the deep=ocean environment are suimnarized as follows: 



Low ambient temperature 



Biological environment 



High hydrostatic pressure 



Stress 



Chemical environment 



Electrochemical effects of immersion in an electrolyte 



Water movement 



These factors, separately or in combination, may operate to pro- 

 duce one or a combination of the following effects which may change 

 certain properties of the materials exposed to this environment : 



