Recently in Halifax, Nova Scotia, the Royal Canadian Navy (RCN) commenced Exercise VIPERFISH MERCY 2025, its largest annual submarine medical and mass casualty training exercise. The exercise runs from October 22 to 29, 2025, and brings together Canadian Armed Forces (CAF) personnel, NATO allies, and international defence partners to strengthen readiness and interoperability in submarine search and rescue (SUBSAR) operations.

Hosted aboard His Majesty’s Canadian Ship (HMCS) William Hall, a Harry DeWolf-class Arctic Offshore Patrol Vessel, VIPERFISH MERCY integrates the Submarine Medical Course with realistic rescue scenarios. These include both surface and submersible phases designed to simulate high-risk environments and test casualty movement, triage, and medical coordination under pressure. The entire exercise is simulated and takes place aboard thew HMCS William Hall while alongside at Canadian Forces Base (CFB) Halifax.

International participants from Singapore, Australia, the Netherlands, the United Kingdom, Israel, and Malaysia have joined Canadian personnel for the exercise, supported by staff from Germany, the United Kingdom and United States. Their collaboration reflects Canada’s commitment to multinational defence cooperation and global maritime safety. Exercise VIPERFISH MERCY 2025 serves as a national-level test of Canada’s command and control structure for responding to a distressed submarine emergency. It also provides medical personnel with critical hands-on experience in submarine casualty management and mass casualty response, reinforcing Canada’s leadership in submarine medicine and operational preparedness.

The Government of Canada is proud to support this vital training initiative, which showcases the professionalism of CAF medical teams and the RCN’s role in advancing maritime safety and rescue capabilities.

“Exercise VIPERFISH MERCY 2025 reflects the Royal Canadian Navy’s dedication to operational excellence and our leadership in submarine medical readiness. By training alongside our allies in complex, scenario-based environments, we are enhancing our collective ability to respond to emergencies at sea. This exercise underscores the importance of interoperability and the strength of our global partnerships. It also highlights the professionalism and resilience of our sailors and medical teams in safeguarding lives.” Commodore Jacob French, Commander Canadian Fleet Atlantic.

“VIPERFISH MERCY 2025 showcases the innovation and preparedness of our naval and medical personnel in responding to high-risk submarine emergencies. The exercise provides a vital opportunity to rehearse mass casualty protocols in realistic, confined conditions. Working with international partners strengthens our shared readiness and reinforces Canada’s role in global maritime safety. We are proud to lead this initiative and demonstrate the capabilities of the Royal Canadian Navy Captain(N) Preston Mcintosh, Chief of Staff, Maritime Component Commander

ADDITIONAL INFO

  • VIPERFISH MERCY is Canada’s premier submarine medical training exercise. It provides a rare opportunity for military medical teams to rehearse life-saving procedures in simulated submarine emergencies.
  • The exercise features international participants from Singapore, Australia, the Netherlands, the United Kingdom, Israel, and Malaysia, supported by staff from the United Kingdom and United States, working alongside Canadian Armed Forces personnel. This international collaboration helps build trust, shares expertise, and improves coordination in real-world rescue scenarios.•
  • Training takes place aboard HMCS William Hall, a modern Arctic Offshore Patrol Vessel equipped with modular medical facilities for onboard triage and treatment. The ship serves as a platform for both surface and submersible rescue simulations.
  • Medical teams are challenged to manage multiple casualties in confined, high-risk environments. These scenarios test their ability to triage, stabilize, and coordinate care under pressure.
  • Planning for VIPERFISH MERCY began months in advance with detailed coordination across logistics, equipment, and personnel. The exercise reflects the Navy’s commitment to preparedness and operational excellence.