Electrical problem eyed in grounding of tanker

Some steering-control components were used beyond their lifespan, TSB finds

Damaged electrical components in the steering system may have caused the tanker Chem Norma to run aground in the St. Lawrence Seaway last May. The 145-metre tanker stayed stuck off Morrisburg “like a boot in mud” for days.

The Transportation Safety Board said in a report released Wednesday that 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.”

The Chem Norma ran aground early on May 29 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 damaged but no one was injured and there was no evidence of a spill.

The ship drew crowds of spectators to the waterfront and social media buzz among seaway-watchers on both sides of the border.

The Chem Norma was “refloated” June 3 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 per cent to raise water levels by 30 cm near the ship.

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. 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.

(Equipment was) extensively deteriorated and showed clear signs of electrical arcing.