When the British ships HMS Terror and HMS Erebus hauled anchor and sailed west toward the North American Arctic on May 19, 1845, they were embarking on the largest and most publicized voyage of discovery undertaken by Europeans in 300 years.

Under the command of Sir John Franklin, the expedition set out to traverse the fabled Northwest Passage, the much-sought-after shortcut between the Atlantic and Pacific oceans, and a route to the riches of Asia.

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Sir John Franklin's expedition set out to find and traverse the cold waters of the fabled Northwest Passage. (Evan Mitsui/CBC)

While the expedition left England amid much optimism it would succeed, it ultimately ended in the tragedy of lost lives and vessels, and became the greatest disaster in British exploration of the Arctic. A mission led by Parks canada to find the ships resumes this summer.

Franklin was no stranger to the Arctic. In the two decades prior to the 1845 mission, he had been on three expeditions there.

But this time, at an unfit 59 and nearing the end of his naval career, he found himself commanding ships specially outfitted with Industrial Age technology that had not yet been tested in severe Arctic conditions.

The vessels had iron plates on the reinforced bows, retractable propellers and rudders, steam engines and a newly designed internal steam heating system for the comfort of the officers and crew. A three-year supply of tinned food was stowed below.

"Steam power was actually in its infancy, both on land and in the water," says Ryan Harris, a Parks Canada marine archeologist who is leading the agency's efforts to search for the lost Franklin vessels in the Arctic this summer.

"Steam engines were so new, they weren’t purpose-built marine engines, but for locomotives."

Food may have made plight worse

In retrospect, the new Industrial Age features, even if perfectly functional, were simply not enough to save the sailors from disaster, and in fact the food may even have added to their plight.

The two Franklin ships were last spotted by a whaler in Baffin Bay in the Eastern Arctic in August 1845, before ice conditions allowed the two ships to steer a course into Lancaster Sound, the eastern entrance to the Northwest Passage. It was the last time the Terror and Erebus were seen by Europeans.

In September 1846, it is believed that the ships, sailing south down the west side of King William Island, most likely got trapped in ice somewhere in Victoria Strait.

The Franklin expedition tragedy slowly unfolded, with the deaths, over the next few years, of the entire ships' complement of 129.

The crew members' fate was most likely the result of a combination of disease, starvation, possible lead poisoning from the tins and/or the drinking water system, the brutal Arctic winters that they had to endure and perhaps even cannibalism, historians and archeologists surmise.

As well, the expedition simply wasn't equipped for such a long stretch of time stranded in the ice, or for the subsequent treks by the sailors to try to reach civilization.

Lady Franklin's determination

Once the British Navy realized that the Franklin ships were missing, it didn't take long for the searches to begin. The first was initiated by the British Admiralty in 1848 at the insistence of Franklin's wife, Lady Jane Franklin, as well as the British Parliament and media.

It was a three-pronged search, one expedition overland down the Mackenzie River, and two by sea from the east and west entrances of the Northwest Passage.

Even though that effort failed to find the ships, the search wasn't over. Finding the Franklin ships became what could be described as a crusade of epic proportions.

Between 1848 and 1878, there were 30 Franklin expedition searches, both over land and by sea. The cost was high. In the first six years, the British Navy spent more than £600,000 and lost five of its own ships and one charter.

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An artist's rendering from 1859 show relics of the expedition led by Arctic explorer Sir John Franklin. (Hulton Archive/Getty Images)

While the searches did yield expedition artifacts, including human bones, there was still no trace of the ships. Subsequent study of the skeletal remains revealed scrape mark patterns on the bones indicating that cannibalism among the ship’s complement likely occurred.

Historian David Woodman, author of Unravelling the Franklin Mystery: Inuit Testimony, says that attempts to reconstruct the events after 1848 "rest largely on the testimony of the Inuit," whom he says may have been witness to not only expedition members attempting to trek south toward safety, but also to the sinking of at least one of the ships.

"The tales which are preserved [by the Inuit] often contain compelling details without which a complete picture cannot be built," Woodman says. "But, for 100 years, the main stumbling block is that no one paid attention to the Inuit stories."

But people eventually started paying attention, especially after a photo of the frozen face of a Franklin expedition casualty who died 136 years earlier surfaced in the media in the 1980s.

Artifacts but no ships

Owen Beattie, a University of Alberta anthropologist and co-author of Frozen in Time: The Fate of the Franklin Expedition, led the first of 17 Franklin searches that took place between 1981 and 2011.

Other searches have been conducted by private historical and film groups, and by the Canadian government. They have yielded many Franklin artifacts — from diaries and utensils to bones and teeth — but not the ships.

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A flag is raised on Aug. 15, 1904, at a Franklin monument on Beechey Island, where the remains of three sailors from the Franklin expedition were excavated several decades later. (National Archives of Canada/A.P. Low)

In 1984, Beattie’s group from Alberta found three well-preserved bodies of Franklin crew members at gravesites on Beechey Island. It was the photo of one of their faces that received wide media attention.

"There is nothing that brings more immediacy to history than to actually look at the faces of people who have been dead that long, and so well preserved in the permafrost," says Woodman, who was involved in 10 of the late 20th-century searches.

Detailed analysis of the Beechey Island bodies found by Beattie led him to the conclusion that the Franklin crew members "may have suffered, and died, from severe scurvy and lead poisoning."

Since 2008, collaborative efforts between Parks Canada and the Canadian Coast Guard to find the Franklin ships have been unsuccessful, but each year the search area narrows as previous search sites are struck off the charts.

This summer, two ships, the Canadian Coast Guard icebreaker Sir Wilfrid Laurier and a chartered research ship, the Martin Bergemann, are being deployed to search two prime areas where it is believed the doomed ships may be located.

The search will take place over a six-week period in August and September. One search area is just west of King William Island, in Victoria Strait adjacent to the Royal Geographic Society Islands.

The other is northeast of O’Reilly Island, also adjacent to the Royal Geographic Society Islands. Both sites are just east of Victoria Island, the largest of Canada’s Western Arctic islands.

The resurgence of interest right now, says Woodman, is due to "the search technology getting better and cheaper, and a little bit of urgency to find the ships before somebody privately finds them and starts to do treasure hunting."

According to Woodman, Inuit oral testimony indicates that one of the ships sank in water deep enough to still be intact and upright. It's just a matter of finding out exactly where the ships are located. So far, that's been a very elusive goal.