The U.S. Coast Guard is investigating why a Canadian laker exited the navigation channel near the St. Marys River and ran aground.
Laden with a load of stone, the 603-foot bulk cargo freighter Mississagi was outside designated shipping channels when it ran aground in the St. Marys River in April, according to Coast Guard officials.
“The vessel ended up approximately 100 feet (outside the channel) with the buoy on its port side, and the intended channel would be leaving that buoy on its starboard side,” said Lt. Cmdr. Michael Hjerstedt, investigations chief in Sault Ste. Marie, Mich. The unlit can buoy, which was present because of a 4-foot shoal in the area, was stationed properly, according to an aids to navigation survey conducted during the investigation.
The cause of the grounding is still under investigation, though mechanical failure was not apparent.
“Prior to that incident, we did not receive any reports from the vessel reporting any equipment outages,” Hjerstedt said. “We didn’t order any mechanical repairs and the Coast Guard inspectors on scene did not find any material deficiencies that would require us to compel them to repair it.”
Lower Lakes Towing, which owns the vessel, confirmed as much. “It’s human-error-related, but we haven’t finalized the findings or our internal investigation yet,” said Scott Bravener, Lower Lakes Towing president and chief executive.
The incident did not result in any injuries, pollution or damage to the vessel. While Coast Guard officials initially suspected a hull breach due to water in the forepeak, it was later determined to be the result of shifting residual water during the grounding. Coast Guard marine inspectors determined that ballast tanks had no significant damage or ingress of water. A helicopter crew from Air Station Traverse City provided an overflight of the vessel to confirm there was no pollution.
Mississagi was transporting more than 17,000 tons of stone downbound the St. Marys River from Bruce Mines, Ontario, on April 22 when the bow of the vessel ran aground in the Potagannissing Bay, approximately four miles northeast of De Tour Village.
After being aground for four days, lightering efforts allowed the ship to be refloated. Approximately 2,000 tons of stone was offloaded onto a 600-foot tug and barge, also owned by Lower Lakes Towing. A 500-foot safety zone was established during the offload. Traffic was not disrupted.
“There were some concerns (regarding) the makeup of the shoal,” Hjerstedt said. “We were concerned there was jagged rock or limestone in that area, but after our salvage operations, it was determined that the shoal was actually clay.”
The depth of the passage ranges from 42 to 68 feet, Hjerstedt said. West of the buoy — where the grounding occurred — there’s a long, narrow shoal that extends north to south. At the point of grounding, the shoal was marked at four feet.
After the lightering operation, the ship was anchored and underwent an internal and external inspection by Coast Guard marine inspectors and commercial divers. Upon determination that the vessel did not sustain any structural damage, it was cleared to depart.
The Coast Guard has approximately 120 days to complete its investigation. Depending on the results, Mississagi’s owner could be subject to civil penalties.