MORRISBURG – A catastrophic failure of the Chem Norma’s electrical steering system likely caused the grounding of the ship in May, the Transportation Safety Board has concluded.
The oil and chemical tanker ran aground near the village of Morrisburg after it veered off the shipping channel in the St. Lawrence River.
The TSB report released yesterday (Jan. 19) shows the ship “unexpectedly went hard over to starboard while the vessel was steaming at a speed of 11 knots (20 kilometers per hour).”
The crew tried to bring the ship back on track but the steering system wouldn’t respond, locked over in a hard right turn. The crew regained control by flipping to a secondary steering system but not before the Chem Norma would lodge itself on the muddy bottom of the river edge next to a decommissioned lock system (Lock 23).
It look several days and playing with water levels in the St. Lawrence River to free the ship.
TSB inspectors found signs of heat damage and electrical arcing. “All of the (electrical) relays showed signs of damage due to electrical arcing,” the report stated.
There were also issues with documentation of replacing the relays, which had to be changed out at regular intervals, meaning some could have been in service past their lifespan.
The TSB concluded that, although the “precise cause” could not be pinpointed, a “plausible scenario” was that the electrical contacts experienced “temporary mechanical hanging,” causing the locked steering problem.
The Marshall Islands company that operates the Chem Norma has been sent a safety information letter by the TSB, warning it about the equipment. The owner has since contacted the steering system manufacturer to find better electrical relays to handle the demands of the Chem Norma.
The TSB warned that a similar malfunction could happen in Chem Norma’s four sister vessels, which have the same steering system.
There were no injuries or spillage in the May 29 incident.