Debris in steering gear caused bulk carrier to strike navigational aid in Michigan's St Mary's River, NTSB report finds

American Mariner had also been involved in an earlier incident.

On January 2, 2023, the ship ran aground as it was departing the Ontario side of Sault Ste Marie en route to Superior, Wisconsin. The master, acting alone on the bridge during complicated manoeuvres, overshot a turn and grounded on shoals, damaging three ballast water tanks.

"While manoeuvring in confined waters, it is difficult for a single bridge crewmember to effectively drive, lookout, and monitor and use available bridge equipment," the NTSB said in a report following the 2023 incident.