were then weighed and placed in the racks in which they were to be 

 exposed to the deep-ocean environments The individual racks were then 

 wrapped in polyethylene and transferred to the assembly room where they 

 were attached to the STUj, which is shown in Figiires 6 8c "J with the 

 complete specimen load. The assembly room consisted of a large plastic- 

 covered^ humidity-controlled chamber (see Figure 8) which was erected 

 in a warehouse-type building. The hximidity in this chamber was con- 

 trolled at approximately 35 percent relative humidity. 



When the STU was removed from the assembly room for transporation 

 to the ship and the sea-installation site^ it was wrapped in a polyethylene 

 cover with desiccant included. The cover and desiccant were removed 

 about an hour before the actual placement of the STU in the water. 



Evaltiation of Specimens After Exposure to Test Environment 



Immediately after removal of specimens from the ocean environment 

 they will be photographed with color film and then examined by a biologist 

 who will collect, for identification, specimens of any organisms which 

 may be attached. For a discussion of the biological aspects of materials 

 deterioration see NCEL Technical Report R-182, The Effects of Marine 

 Organisms on Engineering Materials for Deep Ocean Use, 



Following the collection of biological specimens, the STU and its 

 contents will be washed off with fresh water, and the test racks and 

 jigs will be removed and dried and cleaned so as to permit examination 

 of the surfaces of the specimens. Pitting depth, edge deterioration, 

 and loss of plate thickness and weight will be recorded. 



Other tests to determine changes in properties such as durometer, 

 hardness, moisture content, resistivity, tensile strength, chemical 

 composition, and elasticity will be conducted as appropriate for the 

 individual materials. 



OCEAN E3WIR0KMEWT EXPERIMENTS 



Deep-Water Experiments 



Submersib le Test Unit (STU), The STU (Figures 6 & 7) is designed 

 for placing specimens and/or instnaments on or near the ocean bottom, 

 exposing its load to the effects of the deep-ocean environment for 

 extended periods of time, and recovering its load at the end of the 

 exposure period. 



