DEEP-OCEAN BIODETERIORATION OF MATERIALS-PART V. Two Years at 5,640 Feet,
  Technical Report R495, Naval Civil Engineering Laboratory, Port Hueneme, CA, by James S. Muraoka, November 1966, 46 pages.

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.