Delicate work unfolds a mile beneath the Gulf; engineers operate submarines via joystick

Delicate work unfolds a mile beneath Gulf

PORT FOURCHON, La. — It is a job that requires the expertise of a rocket scientist and the precision of a surgeon.

Engineers are racing to stem the disastrous oil leak a mile beneath the Gulf of Mexico, relying on a series of highly technical — and in some cases unprecedented — maneuvers.

They have deployed an armada of remote-controlled submarine robots that are essentially turning wrenches to try to repair malfunctioning equipment and cap the leak while spraying chemicals from a wand into the muck to disperse the oil. Men in hard hats are putting the finishing touches on a contraption the size of a four-story building that will be lowered to the floor of the Gulf to capture some of the escaping oil.

Crews have also begun drilling a new well sideways into the gusher of oil so that they can plug it up with concrete. But that solution could take three months to complete as they dig 13,000 feet below the seafloor — the length of more than 10 Empire State Buildings.

“The challenge is unprecedented,” BP spokesman John Curry said Tuesday.

The disaster began two weeks ago with an explosion and fire that killed 11 workers aboard a drilling platform 50 miles out in the Gulf. The well is spewing an estimated 200,000 gallons of oil a day in what could become the nation’s worst environmental crisis.

Crews are working around the clock to keep the spill from reaching the fishing towns and white-sand beaches that line the Gulf Coast.

The weather improved Tuesday and allowed environmental teams to fight back the oil slick as residents anxiously waited to find out when and where the mess might come ashore. Meanwhile, three workers forced to escape on lifeboats after the rig explosion filed a lawsuit Tuesday alleging that they were kept floating at sea for more than 10 hours while the rig burned uncontrollably.

The legal action came as a much less visible task unfolded at the bottom of the Gulf, 5,000 feet down.

It is there that nine submersible robots are carrying out various tasks.

In one case, a robotic arm turned a valve on a broken piece of equipment and transmitted video to crews in a control booth. In another, a submersible applied chemicals with what looked like something a homeowner would use to spray weeds on his lawn. The vehicles are also trying to activate a giant piece of machinery called a blowout preventer that was supposed to stop the oil flow but failed.

The undersea vehicles are the workhorses of the deepwater oil and gas industry, capable of performing chores at depths where people can’t go because of the crushing water pressure. They are the size of a Humvee and are generally operated by a three-person crew using joysticks and video feeds on 40-inch screens.

“Some of those operators can pour cups of coffee, can pick up 600 pounds or pick up an eggshell without breaking it,” said Lou Dennis, vice president of programs for Perry Slingsby Systems, which claims to be the world’s largest maker of the devices.

Officials with BP and the Obama administration have been encouraged by the results of the spraying. The vehicles have been spraying the dispersant at a rate of nine gallons per minute — nowhere near enough to keep up with such a gigantic spill, but engineers believe enough to keep a fair amount of oil from rising to the surface.

Normally, dispersants are applied to floating oil. This is the first time these chemicals have been used underwater at such depths.

As of Tuesday, BP spokesman Bill Salvin said the crews drilling the relief well had bored 1,275 feet below the seafloor and had 11,500 feet to go.

“The deeper you go down, the harder it is to drill,” he said.

The effort that has the best chance of success in the short term is the installation of a rectangular containment dome that BP hopes to lower into the Gulf on Thursday or Friday to cover the biggest of the three underwater leaks.

The concrete-and-steel structure is 40 feet tall, weighs nearly 100 tons and is outfitted with valves and pipes that will funnel the crude into a tanker. BP hopes to hook up the device to the ship over the weekend or perhaps as late as Monday.

Such domes have never been tried at this depth because of the extreme water pressure. Salvin noted that about 3,000 feet of water can crush a Navy submarine.

Jason Holvey, a marine engineer, said smaller containment devices have been used in the Gulf, but at depths of only about 300 feet. They were used after Hurricane Katrina, he said, to capture oil spilled from platforms.

One fear is that the petroleum will clog up in the tubes and make it difficult to pump the oil into the tanker.

“We don’t know for sure” whether the equipment will work, Salvin said. “What we do know is that we have done extensive engineering and modeling and we believe this gives us the best chance to contain the oil, and that’s very important to us.”

Despite all the high-tech gadgetry, BP said engineers are not able to determine with any degree of precision how much oil is leaking.

“It’s very difficult with the cameras down there and the way the lighting is impacted by the water to get a decent sense of perspective,” Salvin said. “There is no way for us to put a flow meter on the oil that is coming out.”

Associated Press Writers Michael Graczyk in Houston and Curt Anderson in Miami contributed to this report; Henry contributed from Robert, La.