Finding the wreck of Endurance

Donald Lamont described the background to the Falklands Maritime Heritage Trust taking on this challenge and identified Dr John Shears(Expedition Leader), Mensun Bound (Director of Exploration) and Nico Vincent as the key figures in the team that discovered the wreck.

The three objectives of the Endurance22 expedition were to:

1. Locate, identify and survey the wreck of Sir Ernest Shackleton’s ship Endurance;
2. Bring the story of Shackleton to a new generation through a major international educational and outreach campaign; and
3. Investigate and study the remote western Weddell Sea ecosystem.

The window of opportunity to reach the presumed site of the wreck in the Weddell Sea was tight, limited by the short Antarctic summer. The ship had sunk on 21 November 1915, Capt Frank Worsley calculating the location as 68º 39’ 30” South and 52º 26’ 30” West. Hurley’s photos of the last days of the ship show the collapsed masts as the ice increased its grip. One of the biggest challenges facing the expedition was navigating and operating in the sea ice in the Weddell Sea. At the Endurance wreck site, the sea ice concentration was 100%, and the average ice thickness was 1.4m.

Dr Shears had been Expedition Leader for the Weddell Sea Expedition in 2019 and many lessons were learned from the failure to find Endurance that year. But one positive was the choice of the South African government’s polar research vessel, Agulhas II. The capability of the ship, its Master, Ice Pilot and crew had meant there was no doubt that the ship should be chartered for Endurance22.

As well as the 45 officers and crew of Agulhas II, there was an international group of 65world-leading engineers, technicians, scientists, pilots and media personnel onboard. The subsea team was predominantly French. The Chief Scientist, Dr LasseRabenstein, was from Germany and his team came from Germany, South Africa andFinland. The helicopter teams were South African and American, and the media team largely British.

Dr Rabenstein’s team, together with colleagues from the Alfred Wegener Institute, other German institutions and the South African Weather Service, were vital to the task of navigating through the sea ice to reach the wreck site. Having expected to only be able to reach the site via helicopter, the 2021-2022 season saw the least sea ice ever recorded in the Weddell Sea, which allowed the ship to access the site directly.

Having left Cape Town on 5February 2022, the Expedition reached the survey area on 16 February and began sea ice research and AUV (autonomous underwater vehicle) operations. As the Expedition began its search in temperatures of -17 degrees Celsius, it relied on the latest subsea technology incorporated in the SAAB Sabertooth hybrid AUVs. While those are capable of operating independently, the Expedition had learned from the 2019 search attempt when the AUV was lost forever under the ice, so they always deployed the Sabertooth on a fibre-optic cable, to a depth of 3,008m. The wreck was eventually found at this depth on 5 March.

Beginning his account of the subsea search, Nico Vincent regretted the absence of a French element in the stories of Shackleton the Explorer. He invited the audience to accompany him on an account guided by the works of Jules Vernes. The logistical challenges of assembling equipment in Europe and transporting it to South Africa were exacerbated by the Covid pandemic. The subsea team carried out extensive training in the South of France, testing the equipment and devising engineering solutions to the problems of trying to locate a wreck at 3,000 metres under ice. The ice cover would severely limit the amount of open water that the Sabertooths could be launched into, and could also prevent Agulhas II from manoeuvring.

The pre-defined search area was the size of Inner London at 382km² and the ice forecasts, relying predominantly on satellite images were crucial. The first sign of the wreck was caught by sonar, while 3D sounding and a 3D laserprovided more compelling and detailed images. But the truly stunning, detailed images came from data captured in an orthomosaic by the Sabertooth’s sensors. Nico Vincent allowed the audience a limited glimpse of what the team would be able to reveal fully in the future documentary.

Having found the ship, the second aim of the expedition was to bring this discovery to a new generation. For the Falklands Maritime Heritage Trust, bringing the stories of Shackleton, his men, Endurance and the Antarctic to a young and global audience was a major priority. Donald Lamont described how they worked with Reach the World(a US-based non-profit that brings exploration live into classrooms), the Royal Geographical Society (producing materials for teachers) and Little Dot/HistoryHit (producing live broadcasts, podcasts, social media content and documentary material). The TV historian Dan Snow was the face of the Expedition and inspired a strategy that successfully pulled the different parties together. Onboard ship, Nat Hewit managed all aspects of the media operation and directed the documentary, which will be broadcast on the National Geographic channel next year.

James Gray MP paid tribute to the Endurance22 team’s tenacity and spirit of cooperation which had allowed them to successfully carry out one of the most difficult subsea searches ever undertaken. As Sir Ernest Shackleton said: “Difficulties are just things to overcome, after all”.

Questions

“The sea ice was the lowest ever recorded in the Weddell Sea, was this due to climate change?”

Prof Mike Meredith, British Antarctic Survey, replied:

A big retreat in sea ice has been identified recently, due to many factors, and 2022 was the lowest recorded minimum in the Weddell Sea. There’s no doubt that the effects of climate change on sea ice cover will make the Endurance wreck more accessible in the future.

“Did what you found at the wreck site change the Endurance narrative?”

Mensun Bound, Director of Exploration, replied:

In many ways it did as we discovered that the ship was not crushed, as many had believed. We had expected to find her in pieces, but the images showed that she was remarkably intact. Endurance had incredible strength and is second only to the Norwegian polar expedition ship Fram, as the strongest wooden, non-naval ship ever built.