Oil will flow unimpeded into the Gulf during the cap switch for at least part of the weekend.
If all goes according to plan, the duo of the new cap and the new vessel could collect all the leaking oil by Monday. If successful, the oil will be stopped from escaping into the Gulf of Mexico for the first time since April 20.
Officials are still upholding a mid-August deadline for the leak to be plugged once and for all. Crews are working on drilling two relief wells through which mud and cement will be pumped to stop the leak.
The new containment cap is expected to form a better seal over the well head, to allow more of the oil to be collected and sent up to ships on the surface for collection or burning.
"Technically it's pretty achievable," Allen said. He said if the new cap can't be placed on the well, the old cap will be put back and there are multiple backup caps available in case any one cap fails.
Allen estimates that the combination of the new cap and the new ship should be able to collect 60,000 to 80,000 barrels a day.
The schedule for both efforts has been accelerated to take advantage of what could be a rare window of good weather. The hookup of the new ship, Helix Producer was delayed this week by poor weather. But an unexpected break in weather patterns creating choppy seas provides a window of a week or so with waves of only 1 or 2 feet.
Containing the leak is not the same as stopping the environmental catastrophe that began April 20 when the Deepwater Horizon oil rig exploded, killing 11 workers.
The relief wells remain the best option for a final plug to the leak, at which point cleanup and restoration become the main focus.
Though officials said the first relief well could be finished by the end of July, weeks ahead of schedule, they are quick to point out that such an optimistic timetable would require ideal conditions every step of the way.
- The new presidential oil spill commission will focus on how safety, government oversight and the ability to clean up spills haven't kept up with advances in drilling technology, the panel's leaders say.
The commission will also dig into what it calls the root causes of the BP oil rig explosion, looking deeper than just equipment failures.
- Sea turtle egg evacuations have begun along the Gulf. It is the first step in a sweeping and unprecedented turtle egg evacuation to save thousands of threatened hatchlings from certain death in the oiled Gulf of Mexico. Rescued eggs are transported to a warehouse at Florida's Kennedy Space Center where they will incubate and, hopefully, hatch before being released into the Atlantic Ocean.
Scientists fear that if left alone, the hatchlings would emerge and swim into the oil, where most would likely die, killing off a generation of an already imperiled species.
The Associated Press contributed to this report.