While there is speculation why the 1000 ft Paul R Tregurtha headed off course and went aground in front of Bayfront Park in Duluth this afternoon, there will be a full investigation over the next weeks.
The Tregurtha was pulled free by tugs after several hours sitting in the muck.
In the following video, you can see the Tregurtha start to make it's final turn towards the bridge, but then you hear the emergency horn prior to seeing the boat stop.