would be the spacing of specimen plates. Due to the high foixLing rate 

 in the harbor _, it would be necessary to provide more separation between 

 adjacent specimen plates than is believed necessary for deep-ocean 

 exposure. 



MATERIALS TO BE INVESTIGATED 



Since this is a continuing progrsjn it is not feasible to provide 

 a complete list of all the materials to be tested. The Appendix contains 

 a list of all the materials contained in the specimen load of the first 

 Submersible Test Unit placed in FY=62o Selections of materials to be 

 included in the tests have been based on gleanings from the literature 

 and from the records of meetings held by various naval activities and 

 scientific groups., The major producers of metals^, as well as nonmetals, 

 have been requested to supply their recommendations . In most instances 

 the producers have provided advice^ and in seme cases have supplied 

 samples of production materials for test. 



The Naval Air Material Center at Philadelphia^ Pennsylvania, the 

 U. S. Naval Engineering Experiment Station at Annapolis^ Maryland, the 

 U. S» Naval Underwater Ordnance Station at Newport, Rhode Island, the 

 Naval Ordnance Test Station at China Lake^ California, the Navy Electronics 

 Laboratory at San Diego, California, and some industrial laboratories, 

 as well as NCEL,, have contributed specimens for inclusion in this program. 



EXPERIMENTAL METHODS 



Unstressed Specimen E3q)eriment 



Unstressed roa,terials will be utilized as the primary type of 

 specimens to be exposed in the experimental environments. Where it 

 is feasible (generally a matter of having a sufficient quantity of 

 the test material), rigid sheet materials have been cut to 6 inches 

 by 12 inches in size and moionted in racks. The purpose of utilizing 

 specimens of this size is to reduce the possibility of edge effects 

 obscuring the effects of the environment on normal flat surfaces. 

 Sixteen such plates are shown in Figure 1 in a exposure rack designed 

 for specimen exposure above the water-bottom interface. Similar racks 

 are used for exposure of specimens in the environment of the sediments 

 below the water-bottom interface. As may be noted in Figure 1, each 

 6-inch by 12-inch specimen is in contact with nothing except porcelain 

 insiolators and each set of four specimens is separated from adjacent 

 dissimilar materials by a vinyl separator plate. In this illustration, 

 four replicate sets, each containing four plates of a single material, 

 are shown. 



