Shackleton's Endurance Was Weak From the Start

For more than a century, icy Antarctic waters took the blame for the sinking of Ernest Shackleton's Endurance, touted as the strongest polar ship of its time—but a new study suggests the real culprit was the ship itself. It comes from Jukka Tuhkuri, an ice researcher and naval architect who participated in the 2022 expedition that located the wreck. By reviewing crew diaries, Shackleton's personal correspondence, and examining the wreck itself, Tuhkuri concluded that the ship lacked sufficient internal beams to withstand the pressure of encroaching ice, per the New York Times. This deficiency led the rudder, stern post, and keel to fail, allowing water to pour in and sink the vessel after the crew abandoned it in November 1915.

There were other issues apart from the missing internal beams, including weaker deck beams and frames than with other early Antarctic ships, according to a release. Shackleton may have recognized these flaws before setting sail a year earlier, according to the study published Monday in Polar Record. In a letter to his wife, he admitted the Endurance was "not as strong as the Nimrod constructionally," referencing a more robust ship he'd previously used. He'd also helped another explorer equip his ship with the structural beams Endurance lacked ahead of an earlier Antarctic voyage, suggesting he knew the work was important.

Experts note that the Endurance was originally designed for Arctic hunting, not for being trapped in Antarctic pack ice. But few ships designed to withstand the harshest conditions were available at the time. As explorers raced to chart new ground, they often resorted to retrofitting secondhand ships, ending up with a product they knew presented risks. Diary entries from Endurance's crew members describe subsequent ice compression events putting pressure on the engine room, "where there are no beams of any strength." Capt. Frank Worsley had acknowledged this as "the weakest part of the ship." This challenges the notion that the ship's rudder was its Achilles' heel, torn away by ice in a fatal blow, says Tuhkuri.