INTRODUCTION 



As part of a research program to determine the effects of the deep ocean 

 environment on various materials, the U. S, Naval Civil Engineering Laboratory 

 (NCEL) in March 1962 placed the first of a series of Submersible Test Units, 

 designated STU 1-1, on the ocean floor in 5,300 feet of water at Test Site I off the 

 coast of California (Figure 1). Since then 5 additional STUs have been placed on 

 the sea floor and recovered; these are listed in Table 1 v/ith pertinent information 

 about each STU. 



STU 11-2 was recovered in May 1966 after 13.4 months on the sea floor in 

 2,370 feet of water. A sketch of the STU 11-2 system as installed is shown in 

 Figure 2, The STU was loaded with 2,588 specimens of 81 1 materials. The majority 

 of these materials were metal and metal alloys for the study of corrosion. For 

 studying biodeterioration, nonmetallic materials, such as woods, ropes, glass, rubber, 

 and plastics, were assembled in two bio-racks which were attached to the side of 

 the STU. 



This report describes the materials and presents the methods used for attracting, 

 collecting, and evaluating deep sea fouling and boring organisms and the results of 

 field and laboratory investigations of the materials recovered from STU 11-2. 



Before the materials were exposed in the deep ocean on the STUs, a literature 

 search was made on the effects of deep ocean animals on materials, and the findings 

 of that study were reported in Reference 6. 



RESEARCH METHODS 



Oceanographic Information 



Concurrently with the STU program, numerous cruises have been made to the 

 STU sites to collect oceanographic and biological data. Information has been 

 gathered about the environmental parameters, such as salinity, temperature, dissolved 

 oxygen concentration, and biological activity. Such information is essential in 

 evaluating changes in the materials exposed on the ocean floor, especially the 

 corrosion of metals. The environment for Test Site II (2,370-foot depth) is presented 

 in Table 2. 



