Top Hat Reaches Seafloor - Report

The two-ton containment dome nicknamed the "top hat" descended to the seafloor near the leaking Macondo well overnight, the Associated Press reported Wednesday morning. A crane on Ulstein's M/V Viking Poseidon offshore construction vessel lowered the device.

A much smaller version of the cofferdam structure that proved unsuccessful over the weekend, the top hat is designed to provide less space for natural gas hydrates to form because it will capture less seawater. BP had to abandon its initial containment plan after hydrates accumulated inside the larger container dome, causing the dome to become buoyant and plugging up the 12-inch-wide opening at the top designed to connect to the riser system. Unlike the initial containment approach, BP will place the top hat on the seabed already connected to the riser system.

The New Orleans Times-Picayune Tuesday evening quoted a BP spokesman as saying that the top hat would be positioned on the seabed over one of the two leaks Thursday.

On a related note, the Deepwater Horizon Unified Command reported that the Minerals Management Service (MMS) on Tuesday approved the plan to inject methanol into the containment dome to prevent hydrate formation.