A total of twelve such test assemblies were constructed. In December 

 1965, ten of these were submerged by attaching them to the hull of the submarine 

 USS SQUAW, which was suspended about 35 fathoms below the surface in water 

 over 500 fathoms deep. To compare the effects of shallow-water environment 

 with those of the open ocean, the remaining two assemblies were taken to the 

 area of the NELC Oceanographic Research Tower off Mission Beach, where 

 they were attached to tripods anchored approximately 100 yeirds seaward from 

 the Tower at a depth of 60 feet. They were left for 18 months, during which 

 time the installations were inspected periodically by divers working at the 

 Tower. 



Only five assemblies are discussed here, and these were not exposed 

 to their environments over the total planned test period. One of the packages 

 anchored in the Tower area became loosened from the tripod, drifted to shore, 

 and was returned by a lifeguard. The test specimens aboard the SQUAW were 

 not positioned successfully, because of some misunderstanding. The coils 

 had not been cut when the assemblies were attached to the hull of the SQUAW 

 and the panels, in their original sandwich form, were left floating about 2 fathoms 

 above the hull, so that the individual panels were not properly exposed. It was 

 not until 10 March 1966 that one coil was cut. A package still in sandwich form 

 was retrieved at this time (fig. 3). Scheduling difficulties and bad weather 

 prevented cutting the other coils until September 1967, when another sandwich 

 assembly and the ladder that had been cut loose were retrieved. The five test 

 assemblies examined did, however, yield useful information. 



DISCUSSION OF RESULTS 



Results of the tests are summarized in table 1. When the assemblies were 

 recovered, the glass floats were found to be completely covered with 1-inch-deep 

 fouling. The original cotton mesh had completely disintegrated, but the nylon 

 netting was still intact. The polypropylene line was completely fouled, as were 

 its attachment points to the samples and the rubber chafing guards. In no case 

 had the antifoulant coatings used on the panels protected the adjoming areas. 

 The rubber tubing had attracted more mussels than any other material in the assembly. 



The panels which had been torn away from the tripod had been roughened by 

 the action of the sand and surf, but the condition of the samples coiresponded, in 

 general, to that of the set which remained undisturbed for the entire 18 months. 

 Variations in depth in this shallow-ocean test were small (20 to 45 feet), and 

 could not have confributed significantly to the differences in the results. These 

 differences can only be attributed to the varying effectiveness of the coatings used. 



At both locations there were considerable differences among the unprotected 

 panels as well as among those which had been treated with protective materials. 

 As had been expected, fouling proceeded rapidly on the acrylic plates; differences 

 in fouling between the plates at the two locations can be attributed to the types 

 and population densities of biological life at the different depths. 



