  LNM 21/76--8TH CGD, 5/25/76; THREE CONCRETE BLOCKS, ONE AWASH AND TWO COVERED BY ONE FOOT OF WATER AT LOW TIDE HAVE BEEN REPORTED AND CONFIRMED IN POS. LAT.30-19-49.3N, LONG.87-19-30.6W (NAD 27). THE BLOCKS ARE SOUTH OF THE CHANNEL WITHIN 15M OF THE SH