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Marine transportation safety investigation M23A0169

Table of contents

Loss of life

Cargo vessel Polar Prince and submersible Titan
325 NM SSE Cape Race, Newfoundland and Labrador

The occurrence

On 18 June 2023, the Canadian-flagged cargo vessel Polar Prince was at the Titanic wreck site, 325 nautical miles south-southeast of Cape Race, Newfoundland and Labrador, providing surface support to the submersible Titan. There were 17 crew members and 24 people on board the Polar Prince. Five people from the Polar Prince were on board the Titan and approximately 1 hour and 45 minutes after the submersible began its descent, the support vessel lost contact with it. On 22 June 2023, the United States Coast Guard (USCG) confirmed that debris found on the ocean floor near the Titanic wreckage consisted of pieces of the missing submersible. As a result, it is presumed that the five people on board the Titan were fatally injured.

In accordance with the Canadian Transportation Accident Investigation and Safety Board Act and international agreements, the Transportation Safety Board of Canada (TSB), as the investigation authority of the flag state of the support vessel involved in the occurrence, is conducting a safety investigation (M23A0169) regarding the circumstances of this operation conducted by the Canadian-flagged vessel Polar Prince and the submersible Titan.

Work completed as of 28 June 2023

TSB investigators have finished collecting relevant documents and completed the preliminary interviews with those on board the support vessel Polar Prince. The investigation team has taken possession of the vessel’s voyage data recorder, which has been sent to the TSB Engineering Laboratory in Ottawa, Ontario, for further analysis.

The wreckage from the submersible Titan recovered by the USCG arrived in St. John’s Port (Newfoundland and Labrador). The TSB inspected, documented, and catalogued the materials for its safety investigation. The materials are now in the possession of the USCG.

Work completed as of 6 October 2023

Investigators from the TSB were invited by the USCG to join the salvage expedition for the retrieval of additional wreckage from the submersible Titan during the week of September 25. The materials are now in the possession of the USCG and will be analyzed by the TSB at a later date.

The investigation team is continuing to gather additional information and data, while conducting a review of the information gathered to date.

The purpose of a safety-focused, independent investigation is to find all causal and contributing factors to an accident, without attributing blame or civil or criminal liability. This allows the focus to be placed on addressing safety deficiencies, and on preventing similar accidents from happening again.

Next steps

The TSB will continue to cooperate with the United States, United Kingdom, and France, in accordance with international agreements, as they are “substantially interested states” under the International Maritime Organization’s Casualty Investigation Code.

Media materials

News releases


TSB update on investigation into the occurrence involving the support vessel Polar Prince and the submersible Titan
Read the news release

Deployment notice


TSB launches investigation into a marine occurrence involving the Canadian-flagged vessel Polar Prince and the submersible Titan
Read the deployment notice

Media advisory


TSB to hold media briefing regarding its investigation of the occurrence involving the cargo vessel Polar Prince and the submersible Titan
Read the media advisory

Investigation information

Map showing the location of the occurrence

Class of investigation

This is a class 2 investigation. These investigations are complex and involve several safety issues requiring in-depth analysis. Class 2 investigations, which frequently result in recommendations, are generally completed within 600 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.