Transportation Safety Board of Canada (TSB) released its investigation report into the 2024 grounding of the general cargo vessel Heemskerkgracht in the South Shore Canal of the St. Lawrence Seaway off Kahnawake, Quebec.
What happened
On August 22, 2024, the general cargo vessel Heemskerkgracht ran aground after the main engine shut down due to the activation of a false alarm on the oil mist detector (OMD). The vessel was anchored while awaiting assistance and was later refloated and towed to the Port of Côte-Sainte-Catherine, Quebec. There were no injuries or pollution reported. The vessel sustained minor damage to its hull.
OMDs are used to measure the presence of oil mist in an engine crankcase and, in medium-speed engines like the one in the Heemskerkgracht, shut down the engine when oil mist is detected. These detectors cannot differentiate between oil mist, water vapour, or smoke, which can trigger false alarms. To reduce this risk, the vessel’s OMD was fitted with a heater to prevent vapour buildup.
In March 2023, as part of scheduled maintenance, the Heemskerkgracht’s OMD measuring head was identified for a replacement, and a purchase order was made. However, the vessel received a different model which required an external source of power for the heater, unlike the previous unit, which had a power source built into the head. As a result, the heater was left unpowered, leaving the measuring head vulnerable to false alarms caused by water vapour.
The investigation found that during the occurrence voyage, water vapour built up in the OMD measuring head and caused a false alarm that then triggered an automatic shutdown of the main engine. As a result, the vessel lost propulsion and ran aground in the canal.
Following the occurrence, the vessel operator replaced the OMD measuring head with a unit matching the original model. The measuring head was confirmed to have been installed per the manufacturer’s instructions and was calibrated and tested.
Read the report: TSB Canada – M24C0217 Heemskerkgracht