Section k^ 

 MIDMAI ISLAUIS — U. S. MYAL OPEEJATIMJ BASE 



A47.0j. Location of the Test Station and Test Board 



A test "board of the panel type was Installed July 21, 19^* at 

 the U. S. Ka-ral Operating Base at the Midway Islands, located In the 

 northwestern Hawaiian Islands in the central Pacific Ocean. The test "board 

 was located in the extreme east end of a small "boat haven which has 

 a 50-ft entrance-opening facing northward into the open lagoon. The 

 Tiasin floor is coral and coral sand. The test hoard is protected from 

 "boats hy an untreated wood fender pile which forms part of the dock. It 

 ^Is designated "by the symbol USHX-2. This test "board is still "being 

 'operated, and the resiilts of this test hare "been summarized to the end 

 of 1^1, 



Because of the severity of the combined attack of Llmnoria and 

 Teredlnldae , the original panels were replaced "by 2-inch-1iiick pemels 

 on April 21, 19^5; in November of this year, it was requested that 

 the panels "be removed and replaced "by a new series in which the period 

 of su'bmergenoe would "be reduced from 8 to 4 months. On I>eoem"ber 15, 19^^ t 

 the Naval Operating Base advised that they could not comply with this 

 req.ueBt "because the test "board had "been either totally destroyed or 

 washed away "by strong undercurrents. A new test "board of the ^-panel 

 series was Installed on this last-named date. 



On May 15, 19i»-7, the Naval Operating Base advised that the test 

 "board was lost "because of the failure of the supporting caMe. A new 

 "board, using the 4-panel series, was installed in a more protected 

 location on April 1, 19^7, "but shortly after the first set of panels 

 was forwarded, the test "board was carried away during a storm. A new 

 one was not installed until Octo"ber 1 of the same year. The operation 

 of this test ho^rd is helng continued, and the results of the test 

 have "been summarized to the end of 19^7. 



AI4.7.02 Bydrographlc Pata 



The depth of water where the test "board was Installed was 

 12.25 ft. The "board was Installed so that the top of the upper panel 

 was k ft "below the surface of the water, and the lower panel was 2 ft 

 above the "bottom of the "basin. The tidal range was 1.2 ft, and the 

 velocity of the current was said to "be zero. The temperature of the 

 water at the time of installation was 78° F. A temperature reading 

 of 60° F was reported on August 26, 19^6. The average salinity of the 

 water In the vicinity of the test "board was given as 18,000 ppm. . The 

 "boat "basin was reported as not "being contaminated "by artificial sources 

 other than those nonnally expected for an area where from 20 to 25 small 

 "boats are moored. 



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