Port personnel from early this morning- "It was a container ship MSC Dali just sailed Seagirt rigs escorted had just released and were called back immediately hearing ship may have lost propulsion."

So the ship was leaving it's berth; it was heading out of the harbor. Speculation- On calm days/nights the tugs may not even hook up they may be just "on the ready" because the ship has thrusters to allow it to maneuver on its own. From the posted track seems like it was doing fine leaving port and squaring with the channel heading for center span of bridge and on to the balance of the Chesapeake Bay.

The dock the Dali departed from and the Fracis Scott Key Bridge are very close to one another.

Fun Fact- There is a buoy placed basically between the FSK Bridge and the Seagirt terminal the MSC Dali departed from.https://www.chesapeakebaymagazine.com/star-spangled-buoy-marks-national-anthems-birthplace/