Section 58 

 TACOMA, WASHINGTON — TODD PACIFIC SHIFYAEDS, IMC. 



A58 . 01 Location of the Test Station and Test Board 



A test "board of the panel type was operated at the Todd Pacific 

 Shipyards, Inc., at Tacoma, Washington, from September 15, 19''<^ until 

 March 19, 19^6, when it was discontinued. This board was located approxi- 

 mately 180 ft from the north end of Outfitting Pier No. k, which is 

 approximately 2,880 ft long, located in the Wapato Waterway. It was 

 placed in the axea showing the greatest degree of infestation hy marine 

 horers. Original diver inspections and subsequent removal of piling 

 from the dock has indicated a substantially greater degree of infesta- 

 tion on the piling where the mud line was in deeper water. This test 

 board was designated by the symbol USNTWrl. 



A58 . 02 Bydrographic Data 



The depth of water where the test board was installed was 27.5 

 ft at low tide; the tidal range was given as I6 ft frcan extreme low 

 to extreme high tide; the velocity of the cuj^rent was not reported. 

 The temperature of the water at the time of installation was 57° F 

 at high tide and 56° F at low tide (temperatures taken 27 ft below sur- 

 face at both high and low tides). In both instajices, the tempera tvire 

 was taken at minus 15 ft below 0.0 water. Eight 8-in. sanitary sewer 

 lines expelled sewage under this dock from toilet facilities serving 

 approximately 15,000 people dally. One 8-ln. sewer line outlet was 

 located approxi.Tnn.tely 75 ft from the test board. 



A58 . 05 Marine Borers 



1. Teredlnidae . Teredlnidae , Including Bankla setacea and 

 Teredo ( Lyrodus ) sp . , were active throughout the period of the test, 

 occurring in 11 of the 19 control panels and in all except 2 of the 26 

 test panels. Of the control panels, two submerged for k months were 

 5050 filled; one submerged for 5 months was 75^ filled; and two submerged 

 for 6 and 7 months, respectively, were completely filled. Specimens 

 up to 80 mm long were found in one of the panels submerged for k months. 

 The breeding season extends from the middle of December to the middle 

 of November. 



One of the test panels exposed for k months was filled with 

 specimens up to 190 mm in length. All 11 pajiels submerged for from 

 5 to 8 months were riddled, and several were at least half destroyed, with 

 specimens ranging up to 550 mm in length. The attack by Teredlnidae 

 at this location rated very heavy and appears to be continuous throughout 

 the year. 



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