Thanks to a tip from an Inuit crewmember, researchers working in the waters off Nunavut believe they have found the remains of HMS Terror, the second of the two missing ships of Sir John Franklin's doomed 19th-century Arctic expedition.

Following the suggestion from the crewmember who once saw a mast peeking through water, the research vessel Martin Bergmann diverted its course to a bay on King William Island, where sonar scans indicated the presence of a shipwreck, Royal Canadian Navy Rear Admiral John Newton said.

The Martin Bergmann then sent down a remote-controlled underwater vehicle, operated by a Canadian Navy officer, that captured video images of a well-preserved ship similar to Terror, Rear Adm. Newton said in an interview Monday.

Story continues below advertisement

Historians had long thought that after their two ships were trapped in ice in 1846, the Franklin expedition's remaining 105 sailors perished on a march south. Rear Adm. Newton said the location and good condition of the shipwreck suggest that some survivors had returned north, remanned Terror and sailed it to less hostile waters, hoping in vain to return to safety.

"It sounds like the hand of man was involved in keeping that ship going," he said. "It would have taken a lot of discipline and leadership. … It's a pretty heroic story."

The disappearance of Franklin's British Navy expedition after it set sail in 1845 to chart the Northwest Passage has long been a touchstone of Canadian history. Recent efforts to find the shipwrecks became part of Ottawa's effort to assert Canadian sovereignty in the Arctic.

The Sept. 3 discovery was made by the same partnership that found Franklin's flagship, HMS Erebus, in 2014.

This year's campaign, which started at the end of August, involved a Canadian Coast Guard icebreaker, CCGS Sir Wilfrid Laurier; a Navy vessel, HMCS Shawinigan; and the Martin Bergmann, a former fishing trawler converted into a scientific research vessel by the non-profit Arctic Research Foundation.

The rear admiral said the Martin Bergmann was on its way to meet the other ships when Sammy Kogvik, a crewmember from the Inuit hamlet of Gjoa Haven, revealed that during a fishing trip seven or eight years ago, he had seen what looked like a mast poking out in a King William Island location coincidentally called Terror Bay.

Mr. Kogvik took pictures of the mast but lost his camera and hadn't shared the story until now because he felt the disappearance of his photos had been a bad omen. However, on this trip, "Sammy felt he could trust the people he was sailing with," Rear Adm. Newton said.

Story continues below advertisement

"As soon as he said the story, I knew from his eyes and the way he was speaking that he had something. I'd also heard similar stories in the past four years, so we quickly decided to change our course, to go in to Terror Bay," Adrian Schimnowski, the foundation's operations director, told The Canadian Press.

An official announcement still has to be made but a source at the foundation confirmed that the crew of its research vessel had recently spotted the long missing British ship.

"We're waiting to verify. There is a video. … We're still trying to determine details," said the source.

Rear Adm. Newton said the video showed that the sunken ship had features similar to Erebus and Terror. Both were stout Royal Navy bomb vessels, with reinforced framework to support their mortar armaments. The ships had been picked for Arctic exploration because of their sturdier build.

Terror, a 31-metre three-masted vessel, had been fitted with a locomotive to help power the ship's screw propeller. Rear Adm. Newton said the locomotive's chimney can be seen on the video images.

"The ship is in remarkable condition," Mr. Schimnowski said. "It looks like it gently slipped to the seabed floor."

Story continues below advertisement

In a statement, Parks Canada, which is also involved in the search, said it was checking the details of the discovery with other parties involved in the search.

"The discovery of HMS Terror would be important for Canada, reflecting the ongoing and valuable role of Inuit traditional knowledge in the search and making a significant contribution to completing the Franklin story," the department's communiqué said.

Rear Adm. Newton said the search missions for Erebus and Terror had helped the navy acquire Arctic sailing experience and enabled the Canadian Hydrographic Service to survey the area.

The Martin Bergmann is operated by the Arctic Research Foundation, which is backed by Waterloo-area entrepreneurs Tim MacDonald and Jim Balsillie.

Since 2008 major searches for Terror and Erebus had been narrowed down to two main northern zones – the Queen Maud Gulf and the Victoria Strait – based in part on Inuit accounts and studies of ice movements.

Terror's captain, Francis Crozier, was Franklin's second-in-command. After both ships were trapped in ice and Franklin died on board Erebus in 1847, Crozier led the expedition's survivors on the march in which it has been historically believed they all perished. The latest discovery might add a new twist to the understanding of the expedition's final days.