On July 12, 2026, the Royal Canadian Navy’s Victoria-class submarine HMCS Corner Brook (SSK 878) fired a Mark 48 heavyweight torpedo that delivered the decisive strike, sending the decommissioned U.S. Navy guided-missile cruiser USS Mobile Bay (CG-53) to the bottom of the Pacific Ocean. The event occurred during a multinational sinking exercise (SINKEX) as part of the Rim of the Pacific (RIMPAC) 2026 war games off the northern coast of Kauai, Hawaii.
In a recently released video, the sinking was shown to be a team effort involving many of the submarine’s crew, who were heard to celebrate as the Ticonderoga class cruiser sank.
The Mobile Bay sank in waters roughly 15,000 feet (about 4,570 metres) deep, more than 50 nautical miles offshore. Forces from Australia, Canada, Italy, Japan, New Zealand, Spain, and the United States (including Navy, Air Force, and Army units) participated in coordinated live-fire attacks using a mix of weapons such as HIMARS rockets, anti-ship missiles, AGM-158C LRASMs, and Spike NLOS missiles, before the Canadian submarine’s shot caused the final loss of buoyancy.
HMCS Corner Brook, based in Esquimalt, British Columbia, is a long-range patrol submarine. Its successful engagement marked Canada’s return to RIMPAC with a submarine after a 12-year absence and demonstrated the vessel’s precision strike capability in a complex multinational environment following a major refit and modernization. A Royal Canadian Navy spokesperson noted that the exercise allowed sailors to showcase their expertise and contributions to Canada’s defence program. The U.S. Navy, which hosts the biennial exercise, highlighted SINKEX events as examples of the strength and readiness created by international partnerships.
USS Mobile Bay, a Ticonderoga-class cruiser named for the Civil War Battle of Mobile Bay, was commissioned in February 1987 at the Alabama State Docks in Mobile, Alabama. Over more than 36 years of service, it supported Operations Desert Shield, Desert Storm, and Iraqi Freedom, and provided humanitarian assistance after the 1991 Mount Pinatubo eruption in the Philippines. It was decommissioned on August 10, 2023, at Naval Base San Diego.
RIMPAC 2026, the 30th iteration of the world’s largest international maritime exercise (running from late June to the end of July), involved approximately 30 nations, dozens of ships and submarines, more than 190 aircraft, and tens of thousands of personnel. A second decommissioned vessel, the amphibious assault ship USS Peleliu, was sunk in a separate exercise in the same area on July 17.
The Corner Brook’s torpedo shot, viewed in part through the submarine’s periscope, provided valuable live-fire training in tactics, targeting, and undersea warfare. It underscored the operational recovery of Canada’s submarine force and the practical value of allied interoperability in the Indo-Pacific region.
