Figure 34. Rubber tape, burlap (jute), and plastic tape wrappings 

 over plastic rods and pipe. 



Electrical Cable Insulation Over Single Conductors and Multiconductors. The 

 insulation of the 10-inch-iong electrical cable specimens was examined under a 

 stereoscopic microscope for signs of any biodeterioration and for any physical effects 

 of the deep ocean environment. 



The wood bait pieces were riddled by the borers. However, only silicone 

 rubber insulation and polyethylene Insulation were damaged by borer activity under 

 the bait piece exposed near the sediment, and that damage was slight. The other 

 insulations, such as butyl rubber, neoprene rubber, natural rubber, polyvinyl chloride, 

 nylon, fluorinated ethylene propylene (FEP) and Teflon were unaffected by animal 

 activity or by the deep ocean environment (Figure 35). 



The surfaces of silicone rubber specimens which were exposed about 1 foot and 

 3 feet above the sediment were damaged by the nibbling and biting action of some 

 unknown marine organisms. As a result of this type of damage over the entire surface 

 area (except underneath the area of cable clamps), the thickness of the Insulation 

 was reduced considerably. The silicone rubber cement which was used to seal the 

 ends of some of the cables was not affected. 



Laminated Plastics . The phenolic, epoxy, and melamine resin laminated 

 plastic specimens were not damaged (Figure 36). The results of moisture absorption 

 and hardness tests conducted on these materials are presented In Table 5. 



36 



