[img]http://d.yimg.com/a/p/ap/20100701/capt.766e2c9a7477417983009936b0c0488d-766e2c9a7477417983009936b0c0488d-0.jpg?x=130&y=81&q=85&sig=z8TUOlA05RoFQ_RMkKtifw--[/img]AP - A converted tanker billed as the world's largest oil skimmer is being tested in the Gulf of Mexico, where officials hope it will scrub millions of gallons of oil-tainted seawater.