DEEP-OCEAN BIODETERIORATION OF MATERIALS - PART V. TWO YEARS AT 

 5,640 FEET 



Technical Report R-495 



Z-FO 15 -01 -99-006 



by 



J. S. Muraoka 



ABSTRACT 



As Part V 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 24 months on the floor of the Pacific Ocean at a depth 

 of 5,640 feet. The test specimens were attached to a Submersible Test Unit that was 

 placed on the sea floor on 2 October 1963 and was recovered on 22 October 1965. 

 Preliminary visual examination of the recovered test specimens was made aboard 

 ship, and the final examination, tests, and analyses of these materials were performed 

 at the Naval Civil Engineering Laboratory. 



Most plastic specimens and all rope specimens were covered with bacterial slime. 

 The cotton and manila ropes were severely deteriorated by marine microorganisms. 

 Wood panels and manila ropes were riddled by marine borers. The surface of all the 

 plastic materials in direct contact with wood were deteriorated by these borers. 

 Glass, rubber, and certain plastic materials were not adversely affected. 



The results of breaking-strength tests on ropes, hardness and moisture absorption 

 tests on plastics, and insulation resistance and voltage breakdown tests on electrical 

 insulating materials are presented In this report. 



Distribution of this document is unlimited. 



Copies available at the Clearinghouse (CFSTI) $3.00. 



The Laboratory invites comment on this report, particularly on the 



results obtained by those who have applied the information. 



