Laminated Plastics. The 1 x6x 1/8-inch laminated plastic materials (Figure 31) 

 which were exposed near the sediment and about 3 feet above the sediment were not 

 damaged. Percent moisture absorbed by the plastics was determined by weighing each 

 of the test specimens before and after exposure in the sea. The results are presented 

 in the Appendix. 



FINDINGS 



1. There is considerable biological activity occurring in the sediment at Test Site I. 



2. Marine fouling organisms such as bryozoa, tube worms, and glass sponges were 

 found on rock samples collected in the vicinity of Test Site I in 6,000 feet of water. 



3. Hydroids and sponges were found in small amounts on certain metal specimens 

 and on all of the nonmetallic specimens. Typical fouling organisms such as bryozoa 

 and barnacles were not found on these panels. 



4. Marine microorganisms were responsible for the deterioration of cotton and 

 Manila rope specimens, burlap (jute fibers), and possibly a vinyl plastic tube 

 (NCEL No. 338). 



5. Two species of marine borers were found in wood specimens and have been 

 identified as Xylophaga washingtona Bartsch and Xylophaga duplicata Knudsen. 

 The borers were responsible for the deterioration of the following materials: (1) 

 pine, cedar, oak, maple, ash, and redwood, (2) plastic rods (area under the wooden 

 bait pieces) such as delrin, nylon, polycarbonate. Teflon, cellulose acetate, poly- 

 ethylene, acrylics, and polystyrene, (3) vinyl tubes, and (4) Manila rope. 



6. Electrical cable insulation composed of silicone rubber was deteriorated by the 

 nibbling and biting action of some marine animals. 



7. The following materials in various forms and for various uses were not affected 

 by marine organisms: rubber vacuum tubing; nylon nuts and bolts; nylon and poly- 

 propylene ropes; ethyl cellulose cable clamps; neoprene, butyl, and natural rubber 

 electrical cable insulation; various plastic laminated sheets; and glass microscope 

 slides. 



37 



