DEEP-OCEAN BIODETERIORATION OF MATERIALS - PART IV. ONE YEAR 

 AT 6,800 FEET 



Technical Report R-456 



Y-ROl 1-01-01-042 



by 



James S. Muraoka 



ABSTRACT 



As Part IV of a series of reports on the biological deterioration of materials 

 in the deep ocean, this report covers the data obtained after exposing metallic and 

 nonmetallic specimens for 13 months on the floor of the Pacific Ocean at a depth 

 of 6,800 feet (Test Site I). The specimens were attached to a Submersible Test Unit 

 that was retrieved In February 1965. Preliminary examination of the specimens was 

 made aboard ship, and the final examination, tests, and analyses were performed 

 at the Naval Civil Engineering Laboratory. 



On recovery, most of the plastic materials and all of the rope specimens were 

 covered with bacterial slime. Cotton and manila rope specimens were severely 

 deteriorated by marine microorganisms. Wooden test panels, plastics, and Manila 

 ropes were attacked by molluscan borers. Glass, metals, natural and butyl rubber, 

 and certain plastic materials were not adversely affected. 



The results of breaking-strength tests on ropes, weight loss measurements of 

 wood panels, moisture absorption tests on plastics, and Insulation resistance and 

 voltage breakdown tests on electrical insulating materials are presented. 



Distribution of this document is unlimited. 



The Laboratory invites comment on this report, particularly on the 

 results obtained by those who have applied the information. 



