Depermlng Pier were carried away in May 19^6, when a ship foxiled the 

 pier, and new boardB were then installed at this point. 



The resiilts from these test hoards, the operation of which is 

 still heing continued, haye heen summarized to the end of 19^7. 



A15.02 gydrographic Data 



The depth of water at Pier 317-C, where Test Boards USNC-1 and 

 USNC-IU are located, was given as 28.7 ft; that at the Depermlng 'Pier 

 (320), where Test Boards USNC-2 and USNC-2U are located, as 57.6 ft; 

 and that at the Custom House Pier, where Test Board USITC-5 is located, 

 as 10.3 ft. The mean range of tide was given as 5.2 ft. The current 

 velocity ohservations were made at the Charleston Shiphuilding and 

 Drydock Co. , located ahout one-half mile ahove the Custom House Pier. 

 These ohservations showed velocities ranging from a maximum of 2.97 miles 

 per hour out in the Cooper Elver to 0.5 mile per hour at inshore loca- 

 ticais coii5)ara'ble to those velocities of the test hoard installations. 

 The maximum current velocity at the Depermlng Station is prohahly in 

 excess of 3 miles per hour, and along the outside face of Pier 317-C it 

 is at least 3 miles per hour, with stroiag eddy currents prevailing 

 hetween the piles where the test hoard is located. The temperature of 

 the water at the time of installation was given as approximately 82° F. 

 Analysis of the water suhsequently suhmitted show that the hacterial 

 content is high in coliform organisms. This condition was expected to 

 continue, hecause raw sewage and other waste matter was continually 

 heing dun5>ed into the Cooper Elver hy the various communities along it, 

 including the city of Chaxlestoci. At Pier 317-C the chloride content 

 of the water was given as lf,l«-00 mgm per liter and the pH reading as 7.7. 

 At the Depermlng Station the chloride content was given as 6,500 mgm per 

 liter and the pH as 7.9; at the Custom House Pier the chloride content 

 was given as 10,700 mgm per liter and the pH as 7.9. 



AI5 . 03 Marine Borers 



1. Teredinidae . Terefilnldae occurred irregularly in the control 

 panels at each of the five locations, hut their hreedlng season was 

 limited to May through September, Octoher, or November at the different 

 locations. Maximum lengths of 11, 11, kO, 12, and k^ mm were recorded 

 inUSNC-1, USNC,1U, USNC-2, USNC-2U, and UBNC-3, respectively. One of 

 the control panels in USNC-2 was 30^ filled with Teredinidae . Teredinidae , 

 including Bankla gouldi , Teredo navalis, and T. ( LyroduB ) sp. were active 

 at all locations except USNC-IU throughout most of the period covered hy 

 the test. In USNC-1 at Pier 317-C, several test panels were filled or 

 riddled with specimens up to 2li-0 mm in length. In USNC-2, which was suh- 

 merged at the lower depth at the Depermlng Station, the majortty of the 

 test panels were filled or riddled with specimans up to 300 ma in length. 



71 



