GRAND ISLE, La. (AP) -- A cap collected some of the oil spewing out of the blown-out Gulf well, but black crude was still leaking into the sea, and officials said they won't know until later today how the device is working.
It's the latest bid to contain -- not plug -- the nation's worst spill. Even if the cap is successful, it will not collect all the oil coming out. Stopping the leak is still months away.
But officials were optimistic when the inverted funnel-like system, wrapped in hoses and more sophisticated than previous devices, started pumping oil and gas to a tanker on the surface.
Coast Guard Adm. Thad Allen, the government's point man for the disaster, said a very rough estimate of current collection would be about 42,000 gallons a day, though he stressed he wasn't certain.
"Progress is being made, but we need to caution against over-optimism," he said.
President Barack Obama was set to visit the Louisiana coast today, his second trip in a week and the third since the disaster unfolded following an April 20 oil rig explosion. Eleven workers were killed.
Meanwhile, waves of gooey tar blobs were washing ashore on the white sand of the Florida Panhandle and nearby Alabama beaches as a slick from the spill moved closer to shore.
Spotters who had been seeing a few tar balls in recent days found a substantially larger number before dawn on the beaches of the Gulf Islands National Seashore and nearby areas, a county emergency official said. The park is a long string of connected barrier islands near Pensacola.
BP's Chief Operating Officer Doug Suttles said it will be later in the day before they know how much is being captured.