Resistance of Organic Materials and Cable 

 Structures to Marine Biological Attack 



By LLOYD R. SNOKE 



(Manuscript received June 6, 1957) 



The increasing use of submarine telephone cable has resulted in the need 

 for information on the performance of organic materials and cable structures 

 under marine conditions. Recently, Bell Telephone Laboratories initi- 

 ated a program to acquire fundamental data on the resistance of a wide 

 range of organic materials, as well as immediately applicable engineering 

 information. The present progress report describes the program which in- 

 cludes accelerated, laboratory-microbiological tests, as well as the ac- 

 quisition of data from actual marine exposures. In biochemical oxygen de- 

 mand-type tests conducted to date polyethylene was not utilized as a carbon 

 source by marine bacteria. Polyvinyl chloride plastics served as a source of 

 energy for the organisms depending on the way in which the materials were 

 plasticized. Five elastomers were utilized by the bacteria. There has been a 

 steady rise in capacitance values for GRS-insidated conductors exposed in 

 sea water and sediment under laboratory conditions for thirteen months. 

 These increases appear due to biological activity on the insulation. The gen- 

 eral performance of materials undergoing marine exposure is reported in- 

 cluding reference to penetration of a few synthetic materials by marine 

 borers. Brief mention is made of the examination of submarine cable samples 

 from service. 



I. INTRODUCTION 



As a result of the increasing use of submarine telephone cable, there 

 is a growing demand for information on the performance of organic 

 materials and cable structures under marine conditions. Particularly im- 

 portant is the need for data on the resistance of materials to attack by 

 marine organisms. Although considerable published information exists 

 on the behavior of natural organic materials such as wood, jute, hemp 

 and the like, there is virtually no data on plastics, elastomers, casting 

 resins or similar materials. 



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