INTRODUCTION 



The tests described here are part of a continuing effort to find methods for 

 protecting the various materials used in constructing naval equipments from the 

 damaging effects of the ocean environments.''^ Such tests, because of the 

 equipments and procedures they involve, must be scheduled when dock and pier 

 areas are available and, often, when assistance may be provided by ships and 

 by the divers and photographers who work in support of underwater research 

 activities. 



About two years ago, we were informed, with very short notice, that the 

 hull of the submarine USS SQUAW would be available to us for submerging samples 

 for underwater testing. To take advantage of this opportunity, we prepared test 

 specimens from the limited number of materials and protective coatings at hand. 

 Ten assemblies of these specimens were submerged aboard the submarine hull 

 approximately 20 miles at sea. Two similar assemblies were submerged in the 

 Pacific Ocean in the vicinity of the NELC Oceanographic Research Tower about 

 1 mile off Mission Beach, California. 



This report is a record of the results obtained with the two assemblies 

 submerged near the Oceanographic Tower and three of the ten submerged aboard 

 the SQUAW. The other seven are to be periodically retrieved and examined over 

 a period of 10 years. 



TEST PROCEDURE 



Each test package consisted of eleven panels of various materials, 

 measuring 12 by 12 inches, joined at tihe sides m a ladder-like arrangement by 

 lengths of '/4-inch polypropylene line (fig. 1). The panels were attached 1 foot 

 apart, with the lines extending continuously to about 10 feet below the last sam- 

 ple. Heavy, reinforced rubber hose was used for chafing guards at the holes 

 where the line passed through the samples. The samples were stacked, with a 

 glass-ball float attached at the top and a %-inch-thick board at the bottom. The 

 float was covered with cotton mesh which had been further reinforced by 

 2x2x';/-inch nylon netting. Attached at the top of the glass ball was a coil, or 

 "halo," of polypropylene cord. A line was laced up and down from the board 

 to the halo, all around the sandwich, with the 10 feet of line below the last 

 panel left free for use in securing the assembly at the desired location (figs. 2 and 3). 

 Cutting the coil would then release the float, which would pull the entire ladder 

 upright and so expose each individual test specimen to the seawater. 



Navy Electronics Laboratory Report 1026, Investigation of Sonar Diaphragm Coatings, 

 by J.C. Thompson, R.K. Logan, and R.B. Nehrich, 17 March 1961 



Navy Electronics Laboratory Report 1199, Wire Cables for Oceanographic Operations, 

 by J.C. Thompson and R.K. Logan, 13 November 1963 



