An Evergreen Marine-owned container ship became grounded off Baltimore for five weeks as a result of veering off course in Chesapeake Bay’s Craighill Channel, according to authorities.

The 12,118-teu Ever Forward (built 2020) had just left Seagrit Terminal with 4,964 boxes on the night of 13 March, when it soon failed to make a right turn and ended up in the shallows.

“It left the channel. Instead of going straight south, it veered a little to the southeast and into shallower water, which is why the entire hull then became lodged in the sea bottom,” Sean Fitzgerald, a spokesman for incident commander Witt O’Brien’s, told TradeWinds.

“The channel is 50 some feet deep, but then when it veered off course, it went into an area where it was only 24 feet deep and the [draught] of the ship is 42.”

A unified command that also included the US Coast Guard and salvor Donjon-Smit freed the ship on Sunday morning with six tugboats during a full-moon tide and after removing 500 boxes.

The group also directed more dredging to a depth of 43 feet after failing to dislodge the ship on 29 and 30 March with tugs and pull barges.

The Coast Guard is still investigating why the vessel went straight off course instead of making the right turn.

“It wasn’t far, that’s for sure, but I don’t have the exact distance,” he said.

“We don’t know if it was human error, if it was mechanical error.”

It is possible that the ship’s containers may have caught the wind like a sail, but other laden boxships made it through the channel that day without any issues, he added.

“If that were the case, there would have been a lot of other ships, I think, that would have had that same experience,” he said.

“They don’t know. They just don’t know.”

He added that the Coast Guard is questioning all parties involved with the incident, including Evergreen Marine, the harbour pilot who was guiding the ship and the crew.

“I have not heard of any time frame for the investigation, but it’s obviously going to be sooner than later,” he said.

“And they’re obviously looking at the mechanics of the ship to see if there is any kind of mechanical failure.”

Calls to the Coast Guard were not immediately returned.