Section 25 

 ST. THOMAS, TIRGIW ISLAEDS — U. S. MTAL SUBMAEIHE BASE AT KRUM BAY 



A25.01 Location of the Teat Station and Teat Board 



A test "board of the panel type was operated at the U. S. Naval 

 Submarine Baiae at Krum Bay on the southern aide of St. Thomas, Virgin 

 Islands, from July 1, 19kh until the end of April 19^7, when it was 

 discontimied "because of the scheduled inactivitation of this Base "by June 

 50, ISkl. This test hoard was suspended from a steel "brace attached to a 

 creosoted wood pile which was reported to he under attack hy marine "borers. 

 The pile is located in a cove of Krum Bay, which is approximately I60 

 yds hy 275 y^js and is landlocked on three sides. The test "board was 

 designated hy the symhol USKVT-1. 



A25.02 H ydropraphic Data 



The depth of water where the test hoard was installed was 12 ft, 

 average tidal range O.7 ft, velocity of the current zero. The temperature 

 of the water at the time of Installation was 84° F. The salinity of the 

 water was reported to "be '^k parts per thousand. The water in the cove 

 is subject to pollution from the effluent lines from three domestic sewage 

 septic tanks, one on the east side and two on the west side, and from an 

 outlet of a storm sewer on the eastern side. Further pollution of the 

 water is caused during heavy rains when surface water runs into the "bay. 



A25 . 05 tfarine Borers 



1. Teredlnidae . Teredinidae , including Teredo ( Lyrodus ) sp. and 

 Teredo sp . , were more or less active throughout much of the period of the 

 test. In the control panels, they occurred In l^l- of the 51 received {k 

 su"bmerged during the latter part of 19^6 were not received), "but did not 

 appear in a panel until after March 1, 19*«-5. Teredlnidae recorded were 

 mostly minute pits or embryonic specimens up to 10 mm in length, and were 

 observed in one panel submerged for a scant month, and up to 60 mm in a 

 panel inadvertently left submerged for 5 months. Teredlnidae occurred 

 erratically in 2h of the 55 test panels, attaining a mazimiun length of 



200 mm in a panel submerged for 8 months . The largest- number in ajoy one of 

 these panels was kO borers. The breeding season at this location appeared 

 to be more or less continuous. The attack rated slight In 19^5 and moderate 

 in 1946 and 19^7. 



2. Limnoria . L-twnoria were vastly more prevalent than the 

 Teredinidae »Tiri occurred in every control ajid test panel received. The 

 attack ratings in the control panels ranged up to slight. In the test 

 panels, th.ere was a rapid and progressive increase in the • Limnoria 

 population from the time the panels were submerged, until the attack rated 



116 



