A 100-ton concrete-and-steel contraption designed to siphon off the oil fouling the Gulf of Mexico was being hauled to the spot in the sea where a blown-out well is spewing hundreds of thousands of gallons of petroleum a day.
Engineers hope it will be the best short-term solution to controlling the leak that has only worsened since it began two weeks ago.
A rapid response team planned to head to the Chandeleur Islands off Louisiana's coast Thursday to look into unconfirmed reports that oil from the spill had arrived there, Coast Guard Petty Officer Erik Swanson said.
A boat hauling the specially built containment box and dome structure pushed off Wednesday evening from the Louisiana coast and was expected to arrive at the site of the disaster sometime Thursday.
The Joe Griffin will meet up with another BP-chartered boat, the Boa Sub C, a Norwegian vessel that will use a crane to lower the contraption to the seafloor to cover the gusher of oil spewing from the seabed -- something that has never been tried before at such depths. BP spokesman Bill Salvin said the drop is expected at about noon on Thursday.
The dome-like top of the structure is designed to act like a funnel and siphon the oil up through 5,000 feet of pipe and onto a tanker at the surface. Oil has been gushing into the Gulf of Mexico at a rate of at least 200,000 gallons a day since an offshore drilling rig exploded and sank last month, killing 11 people.
"We're a little anxious. They're gonna try everything they can. If it don't work, they'll try something else," Capt. Demi Shaffer told The Associated Press aboard his boat just after it set off. The AP is the only news organization with access to the containment effort.
A 12-man crew aboard a supply boat was carrying the precious cargo. The 280-foot Joe Griffin, owned by Edison Chouest Offshore, also was involved in helping fight the fire that resulted from the oil rig explosion. The vessel is named for a boat captain who worked with company founder Edison Chouest, when Chouest was still in the shrimping business.
The operator of the oil rig, BP PLC, has tried several high-tech undersea tactics to cap the leak. The containment dome endeavor is unprecedented and engineers are fully aware of the risks.
First, crews need to properly position the four-story structure above the well as it sinks deep into the mud at the bottom of the Gulf with the help of a remote-controlled robotic submarine. A steel pipe will be attached to a tanker at the surface and connected to the top of the dome to move the oil.
"It's very dark down there ... and we will have lights on the (submersibles), and we know exactly where to put this and guide it into place," said David Clarkson, BP's vice president for project execution.
That process presents several challenges because of the frigid water temperature -- about 42 degrees Fahrenheit -- and exceptionally high pressure at those depths. Those conditions could cause the pipe to clog with what are known in the drilling industry as "ice plugs." To combat that problem, crews plan to continuously pump warm water and methanol down the pipe to dissolve the clogging.
They are also worried about volatile cocktail of oil, gas and water when it arrives on the ship above. Engineers believe the liquids can be safely separated without an explosion.
Coast Guard Rear Adm. Mary Landry tried to moderate expectations that the containment box would be a silver bullet.
"I know we are all hoping that this containment system will work, but I want to remind everybody that this containment system is a first of its kind deployed in 5,000 feet of water," Landry said.
Asked to handicap the odds of success, Bob Fryer, a senior executive vice president for BP's Deep Water Angola, offered up this assessment: "This has never been done before. Typically you would put odds on something that has been done before."
Fryer also said BP is exploring a technique in which crews would reconfigure the well that would allow them to plug the leak, but that effort is a couple weeks off.
The containment effort comes as dozens of boats were deployed across the Gulf to fight back the slick at the surface, including setting fires to burn off oil and laying booms to soak up the crude and block it from reaching the coast.
While people anxiously wait for the mess to wash up along the coast, globules of oil are already falling to the bottom of the sea, where they threaten virtually every link in the ocean food chain, from plankton to fish that are on dinner tables everywhere.
Hail-size gobs of oil with the consistency of tar or asphalt will roll around the bottom, while other bits will get trapped hundreds of feet below the surface and move with the current, said Robert S. Carney, a Louisiana State University oceanographer.
"The threat to the deep-sea habitat is already a done deal -- it is happening now," said Paul Montagna, a marine scientist at the Harte Research Institute for Gulf of Mexico Studies at Texas A&M University-Corpus Christi.
Scientists say bacteria, plankton and other tiny, bottom-feeding creatures will consume oil, and will then be eaten by small fish, crabs and shrimp. They, in turn, will be eaten by bigger fish, such as red snapper, and marine mammals like dolphins.
The petroleum substances that concentrate in the sea creatures could kill them or render them unsafe for eating, scientists say.
"If the oil settles on the bottom, it will kill the smaller organisms like the copepods and small worms," Montagna said. "When we lose the forage, then you have an impact on the larger fish."
Making matters worse for the deep sea is the leaking well's location: It is near the continental shelf of the Gulf where a string of coral reefs flourishes. Coral is a living creature that excretes a hard calcium carbonate exoskeleton, and oil globs can kill it.
Scientists are watching carefully to see whether the slick will hitch a ride to the East Coast by way of a powerful eddy known as the "loop current," which could send the spill around Florida and into the Atlantic Ocean. If that happens, the oil could foul beaches and kill marine life on the East Coast.
The cause of the rig explosion is still not known, but investigators from multiple federal agencies are looking into the matter. The rig owner, Transocean Ltd., said in a filing with regulators Wednesday that it has received a request from the Justice Department to preserve information about the blast.
Associated Press Writer Ray Henry contributed to this report from Robert, La. Weber contributed from aboard the Joe Griffin supply boat carrying the containment box in the Gulf.