Sightseers in Duluth got an unexpected and up-close look at the longest ship on the Great Lakes on Saturday, when it ran aground about 50 feet from shore off Bayfront Park in Duluth.

The Paul R. Tregurtha, known as "The Queen of the Lakes" because of her size, become mired in shallow water about 3:15 p.m.

The Tregurtha was departing with a full load of coal when it failed to negotiate the turn toward the Aerial Lift Bridge, said Adele Yorde, spokeswoman for the Duluth Seaway Port Authority in comments to the Duluth News Tribune.

“It was making the turn to go under the lift bridge, but it didn’t turn,” she said. “It went straight toward Bayfront Park.”

Jeremy O'Connor, who works at the Great Lakes Aquarium in Duluth, says he saw the 1,013-foot boat leaving the harbor when it appeared to miss a turn and head straight for Bayfront Park, where it got stuck.

"I heard it blow its horn at least eight times to most likely warn people near the shore." It's not clear if the ship sustained any damage.

The Tregurtha settled only about 50 feet from shore, and onlookers reported that, despite the bow thrusters churning, it appeared to be stuck. Later, tugs and boats from the Coast Guard worked to free the freighter. It remained off Bayfront Park until about 7:20 p.m., when it was freed, according to a tweet posted by the Duluth News Tribune.

O'Connor, who's from Duluth, first noticed the ship "not looking quite right" around 3:15 p.m. At that point, the Aerial Lift Bridge was up waiting for the huge ship to depart but the bridge went back down when the ship became stuck.

According to the Interlake Steamship Co., the Tregurtha can carry up to 68,000 gross tons of taconite pellets or 71,000 net tons of coal. The Duluth Shipping news says the ship comes to Duluth about once a week and almost always loads coal, usually for Detroit Edison power plants.