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 additional STU's were placed on 

 the sea floor and these are listed in Table 1 with pertinent information about each 

 STU. 



STU 1-4 was recovered in July 1965 after 13 months on the sea floor in 

 6,800 feet of water. A sketch of the STU 1-4 system as installed is shown in 

 Figure 2. The STU was loaded with 1,852 specimens of 567 materials (Figure 3). 

 The majority of these materials were metal and metal alloys for the study of corro- 

 sion. For biodeterioration study, nonmetallic materials, such as woods, ropes, 

 and plastics, were assembled in two aluminum racks (bio-racks) and then attached 

 to the side of the STU for exposure in the deep-ocean environment. 



This report presents the materials and 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 1-4. 



RESEARCH METHODS 

 Oceanographic Information 



Concurrently with the STU program, numerous oceanographic and biological 

 data-collecting cruises to the STU sites have been conducted. These have produced 

 information about the environmental parameters, such as salinity, temperature, 

 oxygen content, 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 I (6,800-foot depth) is presented in Table 2 

 and in an unpublished report. * 



Test Site I was selected because the area provides a nominal 6,000-foot depth 

 reasonably representative of the open-sea conditions in the eastern part of the Pacific 

 Ocean. It is located about 80 nautical miles southwest of Port Hueneme, California. 



U. S. Naval Civil Engineering Laboratory. Oceanographic data. No author. 

 Port Hueneme, Calif. In preparation. 



