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Marine transportation safety investigation M20C0101

The TSB has completed this investigation. The report was published on 30 July 2021.

Table of contents

Crew fall overboard after workboat struck by mooring line

Unregistered workboat belonging to the bulk carrier Manitoulin
St. Clair River, near Sombra, Ontario

View final report

The occurrence

On , 3 of the Manitoulin’s crew members were crossing over a submerged mooring line in the vessel’s workboat while proceeding to shore near Sombra, Ontario, when tension came on the line and it struck the workboat. The impact caused all of the crew members to fall overboard. One of the crew members swam to shore and the other 2 re‑boarded the workboat. No injuries were reported.

Media materials

News releases


Unmitigated mooring line hazards led to three people falling overboard from a workboat
Read the news release

Investigation information

Map showing the location of the occurrence


Photo of Mélissa St-Jean

Ms. Mélissa St-Jean has been a senior marine investigator at the Transportation Safety Board of Canada (TSB) since 2016.

Prior to joining the TSB, Mélissa has worked at the Canadian Coast Guard for 10 years in various positions and recently as acting Regional Supervisor in Search and Rescue. She also worked for 4 years as Marine Safety Coordinator for the Société des traversiers du Québec.

In addition to being a certified ship’s navigation officer, Ms. St-Jean has a college degree in navigation from the Marine Institute of Quebec and a Bachelor of Maritime Studies from Memorial University of Newfoundland.

Class of investigation

This is a class 3 investigation. These investigations analyze a small number of safety issues, and may result in recommendations. Class 3 investigations are generally completed within 450 days. For more information, see the Policy on Occurrence Classification.

TSB investigation process

There are 3 phases to a TSB investigation

  1. Field phase: a team of investigators examines the occurrence site and wreckage, interviews witnesses and collects pertinent information.
  2. Examination and analysis phase: the TSB reviews pertinent records, tests components of the wreckage in the lab, determines the sequence of events and identifies safety deficiencies. When safety deficiencies are suspected or confirmed, the TSB advises the appropriate authority without waiting until publication of the final report.
  3. Report phase: a confidential draft report is approved by the Board and sent to persons and corporations who are directly concerned by the report. They then have the opportunity to dispute or correct information they believe to be incorrect. The Board considers all representations before approving the final report, which is subsequently released to the public.

For more information, see our Investigation process page.

The TSB is an independent agency that investigates air, marine, pipeline, and rail 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.