"With hurricane-whipped waves pushing more oil onto the Gulf of Mexico's once-white beaches, the government pinned its latest cleanup hopes Wednesday on a huge new piece of equipment: the world's largest oil-skimming vessel. The Taiwanese-flagged former tanker named the ""A Whale"" is the length of 3 1/2 football fields and stands 10 stories high. It just emerged from an extensive retrofitting to prepare it specifically for the Gulf, where officials hope it will be able to suck up as much as 21 million gallons of oil-fouled water per day. ""It is absolutely gigantic. It's unbelievable,"" said Louisiana State University environmental sciences professor Ed Overton, who saw the ship last week in Norfolk, Va.