Rescuers managed to free a cargo ship several hours after it grounded near the mouth of the Mississippi River on Friday, blocking dozens of vessels that had already been delayed by days of fog.

Coast Guard officials said the Anglo Alexandria was moving freely about 4:20 p.m. Friday, about eight hours after it became grounded in the Mississippi River at mile marker 3.5 near Pilottown.

Several tugs responded to help move the 837-foot deep-draft vessel.

The operation blocked about 50 vessels from entering or exiting the river at one point.

The news that the Anglo Alexandria was free came as welcome news to ship captains, who were already struggling with a larger-than-usual bottleneck at the river entrance due to dense fog over the past few days.

Friday was the first day that a persistent, weeklong fog had lifted, said Michael Bopp, president of the Crescent River Port Pilots Association.

"We were just ready to unbottle everything," he said.

Bopp said groundings like this happen about two times a year. The Pilottown area is notoriously difficult for large ships because the river slows down there, causing silt to accumulate, he said. Sometimes, the silt can pile up quickly.

"You could lose 10 feet of depth overnight," he said.

The area where the vessel was grounded is subject to deep dredging, Coast Guard Petty Officer Lora Ratliff said.

Even after the ship was freed, traffic on the river remained stalled late Friday, she said.

"They are checking to make sure there are no sediment deposits which might endanger other vessels from transiting through," Ratliff said.

She said traffic would resume when that process was completed.

The Coast Guard said it has not received any reports of injuries or pollution from the grounding. The agency is investigating the cause of the vessel’s mishap.

The United Kingdom-flagged Anglo Alexandria was built in China in 2011, according to MarineTraffic.com. The vessel is bound for the Suez Canal.