The ship that slammed into the Francis Scott Key Bridge in Baltimore was re-floated on Monday after being stuck for nearly eight weeks.

The Dali was moved by tugboats “under favourable environmental conditions”, according to the US Army Corps of Engineers.

Moving the ship is the latest step in clearing key shipping routes.

The Dali crashed on 26 March, causing the bridge to collapse and killing six construction workers.

The ship lost power before veering off course and striking the bridge. The collision sent around 4,000 tonnes of debris into the Patapsco River and trapped the boat. An investigation into the incident is ongoing.

The 948ft (289m) ship had remained at the scene and was covered in scrap metal from the bridge, until a controlled demolition last week cleared some of the debris.

The Army Corps of Engineers said that it would take around 21 hours to move the Dali to a nearby terminal.

Doing so first required that ballast tanks aboard the ship – which had been filled with large amounts of water to prevent it from swaying – be emptied, allowing the Dali to rise from the floor of Maryland’s Patapsco river.

At high tide around 0700 EST (1200 BST), five tugboats and several other vessels began moving the newly re-floated Dali 2.5 miles (4km) to a nearby marine terminal. Debris and parts of roadway are still clearly visible atop the ship, which remains heavily damaged.

Officials have previously said that the ship is expected to remain at the terminal for four to six weeks before being moved to Norfolk, Virginia for further repairs.

With the ship moved out of the way, deep-draft commercial vessels are now able to use a 400ft (121m) wide, 50ft (15m) deep portion of the federal shipping channel to enter and exit the port of Baltimore, even as cranes and other equipment remain in place to clear additional debris.

The clearing work will continue until the shipping channel is restored to its original width of 700ft (213m) and all steel is removed from the riverbed.

A total of 21 crew members, most of them Indian, have been left on board the ship. Their phones have been confiscated by the FBI and they have had limited communication with shore. Union officials said earlier this month that “morale has understandably dipped” on board the ship.

The FBI and the National Transportation Safety Board (NTSB) are investigating the collapse.

The sailors will remain on-board “for the foreseeable future” while the investigation continues, although the company hopes they will be allowed to disembark soon after the ship is berthed. Darrel Wilson, a spokesperson for Synergy Marine, the Dali’s Singapore-based management company, told the BBC in a statement on Monday.

“All are in good health and are holding up well,” Mr Wilson said, adding that 24-hour counselling services have been made available.

Pre-prepared Indian food is also being delivered regularly to give the cooks on board a rest.

“The crew are keeping busy with their normal duties on board, as well as assisting with the investigation and the ongoing salvage work. Nobody knows the vessel better than they do, hence their integral role in the future movement of the Dali,” he added.

The city of Baltimore has sued the ship’s owners, Grace Ocean Private Limited, and its manager, Synergy Marine Private Limited, alleging gross negligence and recklessness. The companies have asked a court to limit their liability for the incident.

Authorities in the state of Maryland estimate it will cost up to $1.9bn (£1.5bn) and take more than four years to rebuild the bridge.