The above plastic cylinders with test specimens were attached to 

 cylindrical stainless steel brackets, which were secured to a 10-foot-long 

 aluminum corrosion rack and exposed in the sea (Figure 2). 



Design of Plastic Specimen-Exposure Strips 



For total marine exposure (not in test chambers), some test panels 

 were also secured to a 1/8 x 2 x 12-inch plastic strip with nylon nuts and 

 bolts. The plastic strips were cut from phenolic laminated plastic sheet. A 

 small plastic washer was placed between the test panel and the plastic strip 

 to expose as much metal surface area as possible to the seawater environment. 

 The phenolic strips with test panels, together with test cylinders were then 

 secured to a 10-foot-long aluminum corrosion rack for exposure in the sea 

 (Figure 2). These panels are designated exposed panels. 



The length of submergence, the number of test panels placed inside 

 each test chamber and on plastic strips, and other information are presented 

 in Table 1. 



Sterilization of Test Chambers 



The plastic test chambers covered with membrane filters and the rubber 

 stoppers were sterilized by submerging them in a 0.25% chlorine solution 

 (sodium hypochlorite) for 20 minutes. The germicidal effects of this chlorine 

 concentration in distilled water was tested by inoculating the solution with 

 various species of marine bacteria and conducting a standard laboratory 

 bacteriological test on the inoculated water samples. It was found that the 

 0.25% chlorine concentration destroyed all the bacteria present in the water 

 within 5 minutes. 



Shallow-Water Exposure Site 



Test specimens were submerged in the sea off the end of 400-foot-long 

 Point Mugu Pier, which is located at the head of the Mugu Canyon facing the 

 open ocean (Figure 3). The water depth is about 20 to 25 feet during high 

 tide at this location. It was believed this location would subject the test panels 

 to strong tidal currents and to attachment by various fouling organisms nor- 

 mally found in this area. Rough seas are normally encountered during the 

 winter months (December to March). 



