Published: Jul 10, 2010 12:48 AM EDT
Updated: Jul 09, 2010 9:48 PM EDT

NEW ORLEANS (AP) - The BP oil leak could be completely contained as early as Monday if a new, tighter cap can be fitted over the blown-out well, the government official in charge of the crisis said Friday in some of the most encouraging news to come out of the Gulf in the 2½ months since the disaster struck.

If the project planned to begin this weekend is successful, it would simply mean no more oil would escape to foul the Gulf of Mexico. The well would still be busted and leaking - workers would just funnel what comes out of it to tankers at the surface. The hope for a permanent solution remains with two relief wells intended to plug it completely far beneath the seafloor.   "I use the word 'contained,"' said retired Coast Guard Adm. Thad Allen. "'Stop' is when we put the plug in down below."

Crews using remote-controlled submarines plan to swap out the cap over the weekend, taking advantage of a window of good weather following weeks of delays caused by choppy seas.

The cap now in use was installed June 4 to capture oil gushing from the bottom of sea, but because it had to be fitted over a jagged cut in the well pipe, it allows some crude to escape into the Gulf. The new cap - dubbed "Top Hat Number 10" - is designed to fit more snugly and help BP catch all the oil.  During the installation, the gusher will get worse before it gets better. Once the old cap is removed, oil will pour into the Gulf unhindered for about 48 hours while the new one is put in place, Allen said.

BP also worked on Friday to hook up another containment ship called the Helix Producer to a different part of the leaking well. The ship, which will be capable of sucking up more than 1 million gallons a day when it is fully operating, should be working by Sunday, Allen said.