  NM9/68--(3/2/68);  THE 48' TUG LITTLE NELL HAS BEEN REPORTED SUNK ABOUT ¼-MILE WEST OF THE NORTH DRAW OF THE GREATER NEW ORLEANS CAUSEWAY IN 15' OF WATER IN APPROXIMATELY 30/14/45.00N, 090/07/00.00W (NAD27).  A LEAST DEPTH OF 3' OF WATER WAS REPORTED O