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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 manned submersible commonly referred to as Titan, with 5 people on board, was diving to the Titanic wreck site 325 nautical miles south-southeast of Cape Race, Newfoundland and Labrador. The Canadian-flagged cargo vessel Polar Prince that had been used to transport the submersible to the site was providing surface support to the submersible as it dove. Approximately 1 hour and 45 minutes after the Titan began its descent, the surface support team on the Polar Prince lost contact with it. Search and rescue operations were initiated that evening. 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. There were no survivors.

Update: 28 June 2023

TSB investigators collected relevant documents and materials for analysis and completed interviews with those on board the support vessel Polar Prince.

The wreckage recovered by the USCG arrived in St. John’s Port, Newfoundland and Labrador, where it was inspected, documented, and catalogued by TSB investigators.

Update: 06 October 2023

In September 2023, TSB investigators joined the USCG’s salvage expedition for the retrieval and subsequent examination of additional wreckage from the submersible. All recovered wreckage to date is in the possession of the USCG.

Update: 18 June 2024

The investigation determined that the Titan and its custom-built integrated launch platform were first imported into Canada by land from the United States in June 2021 and again in 2022 through separate border crossings.

In 2021 and 2022, the Titan and its launch platform were transported to various dive sites on the deck of the Canadian-flagged vessel Horizon Arctic. In 2023, the Canadian-flagged vessel Polar Prince was used for transport and support, towing the Titan and its platform to dive sites.

From 2021 to 2023, the Titan conducted 7 dives in Canadian waters and 3 dives in Canada’s Exclusive Economic Zone (EEZ). During this same timeframe it also conducted 19 dives outside Canadian waters and Canada’s EEZ, which included its dives to the Titanic. For each of these dives, the Titan was transported to the dive site from a Canadian port and returned to a Canadian port, using a Canadian-flagged vessel. During these operations, the Titan and its launch platform were not registered or certified in Canada or any other country.

The investigation has also identified other submersibles operating within Canadian waters and Canada’s EEZ, both before and after June 2023. Some are registered in Canada; some are registered outside of Canada; and some are not registered. As a result of this information, the TSB issued a marine safety information letter (MSI 01/24) to Transport Canada advising of the risk posed by submersibles operating in Canadian waters.

Next Steps

The investigation is now in the report phase.

Safety communication


Marine Safety Information Letter 01/24: Submersible operations in Canadian waters

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.