Electrical Fault Grounded a Tanker with Tonnes of Alkylate off Morrisburg

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Damaged electrical components in the steering system caused a tanker loaded with tonnes of alkylate to run aground on the St. Lawrence Seaway.

What happened?

In May 2018, the tanker ‘Chem Norm’ ran aground on the St. Lawrence Seaway and was stuck off Morrisburg for days. The tanker ran aground with a cargo of more than 11 tonnes of alkylate, a high-octane blending component for gasoline, bound for Sarnia.

The ship’s hull, rudder, and propeller were severely damaged but no one was injured and there was no evidence of a spill.

Vessel refloated

On June 3, the tanker ‘Chem Norma’ was refloated by tugs Ocean K. Rusby, Ocean Pierre Julien, and Ocean Tundra. They had the help of the International Lake Ontario-St. Lawrence River Board, which reduced dam outflows by 16 percent to raise water levels rose by 30 cm near the ship.

Investigation reports

On December 19, the Transportation Safety Board said in a report, “While the precise cause for the temporary failure of the vessel’s steering gear control system could not be determined, a plausible scenario is a failure of electrical contacts on a steering system relay that mistakenly triggered a hard-a-starboard order”.

TSB investigators found some of the contacts in the steering control relays of the steering system were extensively deteriorated and showed clear signs of electrical arcing. The TSB investigation found that some relays were being kept in service after their recommended lifespan.

The TSB notified the owner of the Marshall Islands-flagged ship, ASM Maritime B.V., of their findings and warning the same thing could happen on the Chem Norma’s four sister vessels.

The Marshall Islands recommended the Chem Norma’s owner review safety plans in case of loss of steering, especially in a narrow waterway with hazards nearby. The owner also asked the maker of the steering system for control relays that can handle the severe conditions produced by the steering system’s inductive loads.

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Source: Ottawa Citizen