Shackleton’s Antarctic Expedition May Have Been Doomed From the Start

The story of Ernest Shackleton and the crew of the Endurance is one of the best-known tales of exploration and survival ever told. After Shackleton’s plans to be the first to cross Antarctica were foiled when his ship became trapped and crushed in the ice, he pivoted to ensuring every one of his crew returned home safely, leading them across ice floes, the stormy waters of the Southern Ocean and the mountains of South Georgia to carry out a dramatic and successful rescue.

But why did Endurance sink in the first place? Accepted wisdom, promoted by Shackleton himself and by Alfred Lansing, whose 1959 account of the expedition remains a best-seller, held that it was a formidable ship whose only weakness was the rudder. Once ice floes tore the rudder away from the hull, the narrative goes, this otherwise redoubtable vessel was doomed.

But new research suggests that narrative is false—the Endurance was, in fact, suboptimally suited to the task and that Shackleton knew it.

In March 2022, Jukka Tuhkuri of Aalto University in Finland was aboard the icebreaker SA Agulhas II when it discovered the wreck of the Endurance at the bottom of the Weddell Sea. Tuhkuri, whose work involves examining how ships cope with the pressures of sea ice, was not a part of the search but was conducting parallel studies on the sea ice and the load it placed on the hull of the Agulhas II. Following the wreck’s discovery, his professional curiosity was piqued. Might it be possible to apply his expertise to determine the precise mechanism by which Endurance was crushed and sank?

Writing in the journal Polar Record, Tuhkuri explained that he reviewed Endurance’s construction and examined cross sections of its hull to calculate how it would likely respond to ice pressure. He soon found evidence that the ship may not have been as perfectly suited to the mission as long believed.

Launched in December 1912 as the Polaris, the vessel was originally designed to take tourists to the Arctic ice edge so they could hunt polar bears and walruses. However, Tuhkuri says, it didn’t make a single voyage to the northern polar regions.

“The First World War was looming, and it was changing how people behave. Times were getting hard and presumably they started to be not so interested in that kind of activity,” he explains.

Tuhkuri notes that, prior to Endurance’s departure for the Antarctic, The Times of London proclaimed that “although very severe pressure from ice is to be anticipated when the vessel is navigating in ice zone, it must be borne in mind that the vessel has been designed to meet it.”

But in fact, taking tourists through scattered ice in the Arctic summer is a very different proposition from driving deep into miles of unrelenting Antarctic winter pack ice. Tuhkuri’s analysis of the ship’s cross sections revealed that it had a major vulnerability in its machine room. While other parts of the hull were reinforced by multiple thick crossbeams, only one beam stretched across the full breadth of the ship in this area, making the machine room and its surroundings “a weak part of the ship.”

Furthermore, there is evidence that Shackleton knew it. In a letter to his wife, he lamented the fact that Endurance was not as sturdy as his previous Antarctic ship, Nimrod. And in 1911, three years before departing for the Antarctic on Endurance, Shackleton advised the builders of Deutschland, which would precede Shackleton to the Weddell Sea, to reinforce the hull with diagonal crossbeams. Suitably strengthened, when Deutschland was caught in the pack ice, it shuddered under the ice’s pressure but survived.

If Shackleton saw the need to reinforce Deutschland, why didn’t he do the same with Endurance?

Tuhkuri emphasizes that he assessed the ship, not Shackleton’s state of mind, but he notes that Shackleton announced his intention to head south in December 1913 and set sail the following August “So he had just seven, eight months to do everything. And that was his style.”

There is context here. The period from 1895 until Shackleton’s death in 1922 is known as the “Heroic Age” of Antarctic exploration, during which “adventurous men were drawn to this arena like a magnet.” Some, like Norwegians Fridtjof Nansen and his protégé Roald Amundsen, were famed for careful, diligent planning, while their British rivals often took a more impulsive approach—an ethos of “damn the torpedoes, full speed ahead,” pressing onward as far as possible and dealing with problems as they arose.

While Shackleton made do with the best he could assemble in a short time, 20 years earlier Nansen had purpose-built a vessel—the Fram—with a rounded hull and minimal keel so it could rise on top of the ice when squeezed between floes, a design that icebreakers around the world have used ever since. Amundsen later used Fram on his successful journey to the South Pole in 1911.

The writings of the Endurance survivors make clear that the ship’s demise was due to more than the ice snapping off the rudder. Tuhkuri notes that the accounts include the ship’s carpenter recording that “the keel was ripped off” and the captain observing that “Great spikes of ice were now forcing their way through the ship’s sides.”

Rather than placing the blame on the rudder, Tuhkuri concludes, “a more correct explanation would be that Endurance was crushed by ice—simply annihilated, as Shackleton put it—without naming a single reason for the sinking.”

Shackleton later wrote that “no ship ever built by man could live if taken fairly in the grip of the floes and prevented from rising to the surface of the grinding ice.” Endurance certainly couldn’t, but with extensive modifications and added crossbeams, it might have at least had a fighting chance.