The well has been capped, more or less. BP engineers Thursday night guided a containment dome onto the Gulf of Mexico oil well – a desperate and iffy attempt to capture the leaking oil and funnel it to a ship on the surface.

It was not an elegant operation. Furious clouds of oil escaped the “top hat.” Late in the evening, officials with BP and the federal government had not yet announced whether the dome would be any more successful than other efforts in recent weeks.

It was a day crammed with engineering drama. First, BP used robotic vehicles and a pair of giant shears to cut a damaged pipe a mile below the Gulf’s surface. Instead of spewing from multiple leaks in a tangle of bent pipes, the oil and natural gas surged in a single plume from what looked like a deep-sea smokestack.

Then came the dome, lowered by cables, guided by robots, illuminated by lamps in a world without natural light, and carrying with it the hopes of countless engineers and pretty much the entire Gulf Coast.

On the surface, the oil has hit more than 100 miles of Louisiana shoreline. After brushing a barrier island in Alabama, it is poised to tar the white sand beaches of the Florida Panhandle. The area of the Gulf closed to fishing is now larger than the state of Florida.

Today, President Obama will make his third trip to the region since the fatal April 20 explosion on the Deepwater Horizon drilling rig.

Although far from the only crisis of his presidency, the oil spill has been uniquely frustrating for Obama, who told CNN’s Larry King on Thursday that he is “furious at this entire situation. … Somebody didn’t think through the consequences of their actions.”

Tony Hayward, BP’s chief executive, acknowledged in an interview published Thursday in the Financial Times that BP wasn’t prepared for a blowout of this magnitude. “What is undoubtedly true is that we did not have the tools you would want in your tool kit,” he said.

The tool kits must be updated, said Rep. Edward Markey, D-Mass., chairman of the House Energy and Commerce’s energy and environment subcommittee: “From junk shots to top hats, this spill shows that BP and the oil industry paid more attention to drilling ultra-deep instead of creating ultra-safe technologies to prevent and respond to a crisis.”

Also Thursday, the Center for Public Integrity, a nonprofit investigative news organization, published an account of Coast Guard logs that indicated the Coast Guard knew within 24 hours of the explosion that the rig’s blowout preventer had failed and that the well could leak as much as 8,000 barrels a day. The center obtained the logs from Rep. Darrell Issa, R-Calif., who said in a statement: “These documents raise new questions about whether the White House was slow to respond to an incident that was quickly recognized by the Coast Guard as a potentially catastrophic threat to the environment.”

Six weeks to the day after Deepwater Horizon sank, and five days after BP and the government gave up hope for killing the well with blasts of drilling mud, the top hat offered the best chance so far of capturing the leaking oil before it can pollute the Gulf further.

The deep-sea plumbing job made for compelling viewing, especially now that BP has gone to wall-to-wall, multiple-camera coverage, putting the live feed from 12 cameras on its website.

The video has shown robotic vehicles, giant shears, a diamond-edged saw, pipes, hoses, tethers, heavy weights and the infamous blowout preventer that did not prevent the blowout. The submarines and their metallic, pincer-grip arms are joysticked via mile-long cables by technicians at the surface, who take orders from engineers in BP’s war room in Houston.

The first attempt to cut the pipe, with the diamond-wire saw, failed when the saw became stuck for 12 hours, pinched by the pipe. When the saw came free, it still couldn’t cut through the riser because of the loose, rattling drill pipe that is threaded inside and wobbling around, preventing a firm cut. So BP engineers resorted to giant shears Thursday morning.

The cut was highly irregular, but engineers went back with the circular saw, slicing off an attached box and smoothing the edges in preparation for the top hat. The government has estimated that the flow rate from the well could increase 20 percent with the bent pipe no longer partially constricting the oil and gas.

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