* Third vessel partly hooked up, rough seas hinder finish
* Relief wells on target for August finish - commander (Recasts; adds details, quotes from briefing)
By Kristen Hays
HOUSTON, July 6 (Reuters) - A third vessel that will nearly double BP’s (BP.L) (BP.N) oil-capture capacity to 53,000 barrels a day at its blown-out Gulf of Mexico was partially hooked up on Tuesday, but rough seas hampered efforts to finish the job, the top U.S. official overseeing the spill response said.
Retired Coast Guard Admiral Thad Allen said that when that vessel is hooked-up and siphoning oil, government officials and BP will decide in seven to 10 days whether to move to a four-vessel system that can capture up to 80,000 barrels a day.
“It is weather-dependent,” he said of the hookup of the third vessel, which will join a drillship and a rig that collected or burned 24,980 barrels of oil on Monday, according to BP figures. “This is a work in progress.”
Allen answered questions during a visit to BP’s U.S. headquarters in Houston, where he said he was meeting with company officials to discuss the oil-capture systems.
He knocked down talk the first of two relief wells, now less than 300 feet from the bottom of the gushing well, would intercept it and plug the leak in July, up to two weeks early.
Early to mid-August remains the target finish date for both wells, Allen said. Current drilling is slow, with stops and starts, to allow BP to use sensors to ensure the relief well is on the right path, he said.
“The last part of this is the slowest, most meticulous part,” Allen said.
The first well began drilling on May 2, and the second, a backup to the first, was started on May 16.
Allen said the third vessel, a rig called the Helix Producer, will increase BP’s oil-capture capacity to 53,000 barrels a day from the current 28,000.
The rig is at the leak site, but rough seas prompted BP to back off from the target hookup date of July 7 and announce on Monday that the company anticipated the new system would likely start up toward the end of the week.
Six-foot-high (2-metre-high) waves have hampered a complete hookup, Allen said on Tuesday.
Of the current oil-siphoning systems, one channels oil from a containment cap atop failed blowout preventer equipment through a fixed pipe to a drillship. The other siphons oil from the blowout preventer through a hose and pipe to a rig.
An undetermined amount of oil keeps billowing out from under the cap and through vents on top into the sea. A team of U.S. scientists estimates the leak gushes up to 60,000 barrels daily.
The Helix Producer will be the first step toward a new overall system, to be in place this month, involving four vessels that can all disconnect and move quickly if a hurricane approaches, Allen said.
He said that system remains on track for mid-July despite the weather delays for the Helix Producer’s hookup. (Reporting by Kristen Hays; additional reporting by Bruce Nichols, Eileen O’Grady; editing by Jerry Norton)