A second attempt to dislodge an Evergreen Line container ship that has been grounded off Baltimore for almost three weeks proved unsuccessful on Wednesday.

A unified command that includes US Coast Guard (USCG) and salvor Donjon-Smit made the futile second try with seven tugs on Tuesday after dredging vast amounts of mud from around the 12,118-teu Ever Forward (built 2020).

“The attempt to refloat the Ever Forward was unsuccessful last night,” USCG petty officer 3rd class Kelly Reaves told TradeWinds.

She said the unified command, which also includes the Maryland Department of the Environment and incident commander Witt O’Brien’s, will resume the effort with two pull barges in addition to the several tugs on 6 April after dredging to a depth of 13.2 metres.

“That date is subject to change, but as of right now, that is the plan,” she said.

The vessel is “very firmly embedded in the seafloor”, said Sean Fitzgerald, spokesman for the unified command and incident commander Witt O’Brien’s.

The pull barges will be attached to the ship’s stern while anchored to the seafloor, the USCG said.

The barges carry “exceptionally powerful winches that pull chains wrapped around the ship to release it from the seafloor and refloat it for towing back to port”, the USCG added.

The USCG said it continues to enforce a 457-metre safety zone around the ship, while responders continue around-the-clock monitoring for potential pollution and stability.

The Ever Forward became grounded near Chesapeake Bay’s Craighill Channel on 13 March. The Hong Kong-flagged ship is owned by Evergreen’s Taipei-listed Evergreen Marine.

It has protection and indemnity insurance from Norway’s Gard and is classed by UK-based Lloyd’s Register.