The 2- by A- by 30- inch pine wood bait pieces which were fitted around 

 the plastic rod and tube specimens were not recovered because these wood 

 pieces were totally destroyed by the marine borers. However, two 3/4- by 

 3- by 24-inch pine wood pieces which were sandwiched in between two metal 

 plates were recovered and the wood pieces were found riddled by borers. The 

 size of some of the borer tunnels measured about 3/4 inch in diameter (Fig 2). 



A piece of Greenheart, a hard tropical wood specimen, which is considered 

 resistant to marine borers was also riddled by the borers. 



The borers had made nutrerous shallow to deep grooves on the surface of 

 plastic rods and tubes in an area under the wooden bait piece. The plastics 

 damaged by the borers include vinyl plastic, delrin, nylon, polycarbonate, 

 teflon, PVC, cellulose acetate, polyethylene, acrylic and polystyrene. There 

 were over 100 shallow to deep grooves around a 1 inch diameter cellulose 

 acetate rod (Fig 3). Some of the grooves measured over 1/4 Inch In diameter 

 and about 1/16 inch deep. 



The cotton and Manila rope specimens were completely destroyed by 

 microorganisms and marine borers, and only a few pieces of the deteriorated 

 rope materials were recovered. 



Two species of marine borers were found boring Into wood and rope 

 specimens recovered from a depth of 5,300 feet. These have been Identified 

 as Xylophaga washingtona Bartsch and Xylophaga dupllcata Knudsen (Turner, 

 R. D.). However, only Xylophaga dupllcata were found In Greenheart wood. 



The discovery of these Teredo-like borers on wooden test panels exposed 

 at a depth to S,640 feet of water In the Pacific was very surprising 

 (Muraoka, 1964 and 1965), although there have been reports of finding 

 Xylophaga sp. In the Atlantic (Turner, 1961) and in the Tongue of the Ocean, 

 Bahamas (DePalma, 1962). 



FUTURE PLANS 



Investigation of the effects of deep-ocean environment upon materials Is 

 continuing. Plans are being readied to recover two STUs during 1965. One 

 3TU has been exposed on the ocean floor In 5,600 feet for a period of 18 

 months. A second STU exposed at a depth of 6,800 feet will be recovered 

 during the latter part of 1965 after 2 years In the sea. It Is anticipated 

 that Interesting and unusual Information about corrosion and growth of 

 marine life upon materials will be obtained when these are recovered and 

 examined. The results of these findings will be reported. 



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