The Transportation Safety Board of Canada (TSB) has released its investigation report into a July 2017 occurrence in which a tug made bottom contact while transiting the Princess Royal Channel south of Kitimat, British Columbia.
On July 9, 2017, at 04:36 local time, the tug Ocean Monarch, with three crewmembers on board, made bottom contact while towing the loaded cement barge Evco No. 15.
No pollution or injuries were reported. However, the tug's hull, starboard propeller, and nozzle were damaged.
After a damage assessment and actions were taken to prevent fuel from leaking, the tug resumed its voyage to Kitimat using the port engine. It then returned to the Fraser River and a shipyard in Vancouver for repairs.
The investigation determined that the mate, alone on watchkeeping duties, fell asleep while the tug and barge transited on autopilot through the channel's confined waters. At the time of the occurrence, the mate had been on duty for at least eight hours, the master and the deckhand were asleep below deck, and all navigational alarms were disabled.
The mate fell asleep likely as a result of acute fatigue from previous night shifts, chronic sleep disruptions, and circadian rhythm desynchronisation, combined with the low and monotonous workload in the wheelhouse.
The investigation also found that the tug's operator had no strategies in place to mitigate crew fatigue despite a previous occurrence in 2011 where fatigue played a role. Given the tug's 24/7 operations, a three-member crew made it challenging, and at times impossible, to maintain two people on the bridge every night while also ensuring the crew was sufficiently rested.