News release

Unidentified risks led to the 2016 capsizing and sinking of tug near Montreal’s new Champlain Bridge

Gatineau, Quebec, 12 October 2017 – In its investigation report (M16C0036) released today, the Transportation Safety Board of Canada (TSB) found that the capsizing and sinking of the Ocean Uannaq tug off Montreal, Quebec in 2016 was due to a lack of formalized operating procedures and inadequate assessment of the safety risks associated with complex marine operations.

On 1 April 2016, three tugs, including the Ocean Uannaq, were involved in repositioning an excavation barge on the St. Lawrence River as part of the new Champlain Bridge construction project. The Ocean Uannaq and another tug were assisting the Ocean Catatug 1, which was attached to the barge. In preparation for the move, the barge's upstream spuds, used for mooring, were raised before the downstream spuds. When one of the downstream spuds jammed as it was being raised, the barge and attached tug pivoted with the strong current around the jammed spud. The Catatug 1's port wire made contact with the Ocean Uannaq, which combined with the opposing current, created a hydrodynamic effect that led to the rapid capsizing of the tug. The two crew members managed to board the attached tug, and the Ocean Uannaq later sank at 1850. There were no injuries or pollution.

The investigation found that neither the tug's owner nor the operator had assessed the risks of the complex marine operations. Therefore, no operating procedures had been developed to guide masters in the best practices for directing operations, and masters were left to make ad hoc decisions. Safety management and oversight is a TSB Watchlist issue. The need for effective safety management has been demonstrated in a number of other occurrences.

Following the occurrence, the operator invited those involved in the occurrence, along with other key individuals from the construction site, the tug and barge owners, to conduct an internal accident investigation. Following that investigation, the existing shore side procedures were extended to the marine construction operations and the operator implemented procedures to help workers identify and mitigate risks on the work site. The operator also hired an assistant marine superintendent to specifically oversee the marine safety aspects of its operations.


The TSB is an independent agency that investigates marine, pipeline, railway and aviation transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

For more information, contact:
Transportation Safety Board of Canada
Media Relations
Telephone: 819-994-8053
Email: media@tsb.gc.ca