Endurance was the three-masted barquentine in which Sir Ernest Shackleton and a crew of 27 men sailed for the Antarctic on the 1914–1917 Imperial Trans-Antarctic Expedition. The ship, originally named Polaris, was built at Framnæs shipyard and launched in 1912 from Sandefjord in Norway. When one of her commissioners, the Belgian Adrien de Gerlache, went bankrupt, the remaining one sold the ship for less than the shipyard had charged – but as Lars Christensen was the owner of Polaris, as well as of the yard, there was no hardship involved. The ship was bought by Shackleton in January 1914 for the expedition, which would be her first voyage. A year later, she became trapped in pack ice and finally sank in the Weddell Sea off Antarctica on 21 November 1915. All of the crew survived her sinking and were eventually rescued in 1916 after using the ship's boats to travel to Elephant Island and Shackleton, the ship's captain Frank Worsley, and four others made a voyage to seek help.
The wreck of Endurance was discovered on 5 March 2022, nearly 107 years after she sank, by the search team Endurance22. She lies deep, and is in "a brilliant state of preservation". The wreck is designated as a protected historic site and monument under the Antarctic Treaty System.
Design and construction Designed by Ole Aanderud Larsen, Endurance was built at the Framnæs shipyard in Sandefjord, Norway. She was built under the supervision of master wood shipbuilder Christian Jacobsen, who was renowned for insisting that all men in his employment were not just skilled shipwrights but also experienced in seafaring aboard whaling or sealing ships. Every detail of her construction had been scrupulously planned to ensure maximum durability: for example, every joint and fitting was cross-braced for maximum strength.
The ship was launched on 17 December 1912 and was initially christened Polaris after the North Star. She was long, with a beam, and measured 350 tons gross. Her original purpose was to provide luxurious accommodation for small tourist and hunting parties in the Arctic as an ice-capable steam yacht. As launched she had 10 passenger cabins, a spacious dining saloon and galley (with accommodation for two cooks), a smoking room, a darkroom to allow passengers to develop photographs, electric lighting and even a small bathroom.
Though her hull looked from the outside like that of any other vessel of comparable size, it was not. She was designed for polar conditions with very sturdy construction. Her keel members were four pieces of solid oak, one above the other, adding up to a thickness of , while her sides were between and thick, with twice as many frames as normal and the frames being of double thickness. She was built of planks of oak and Norwegian fir up to thick, sheathed in greenheart, an exceptionally strong and heavy wood. The bow, which was designed to meet the ice head-on, had been given special attention. Each timber had been made from a single oak tree chosen so that its natural shape followed the curve of the ship's design. When put together, these pieces had a thickness of .
Of her three masts, the foremast was square-rigged, the mainmast and mizzenmast were both fore-and-aft rigged, making her a barquentine. As well as sails, Endurance had a coal-fired steam engine, making the ship capable of speeds up to .
At the time of her launch in 1912 Endurance was arguably the strongest wooden ship ever built with the possible exception of Fram, the vessel used by Fridtjof Nansen and later by Roald Amundsen. There was one major difference between the ships. Fram was bowl-bottomed, which meant that if the ice closed in against her, the ship would be squeezed up and out and not be subject to the pressure of the compressing ice. Endurance, on the other hand, was not intended to be frozen into heavy pack ice, and so was not designed to rise out of a crush. It was observed on the expedition that she instead tended to resist being crushed by floes until the ice cracked to relieve the pressure.
Shackleton purchase Polaris was originally built for the Belgian explorer Adrien de Gerlache and the Norwegian philanthropist Lars Christensen. Financial problems led to Gerlache pulling out of their partnership, leaving Christensen unable to pay the Framnæs yard the final amounts to hand over and outfit the ship. For over a year, Christensen attempted unsuccessfully to sell the ship, since her unique design as an ice-capable passenger-carrying ship, with relatively little space for stores and no cargo hold, made her useless to the whaling or sealing industries. Meanwhile, she was too big, slow and uncomfortable to be a private steam yacht. In the event, Christensen was happy to sell the ship to Ernest Shackleton in January 1914 for , which represented a significant loss to Christensen as it barely covered the outstanding payments to Framnæs, let alone the ship's total build costs. Author Alfred Lansing reports that he was happy "to take the loss in order to further the plans of an explorer of Shackleton's stature". Shackleton did not have the money at the time, but Christensen was eager for him to purchase the ship and paid the deposit himself. After Shackleton purchased the ship, she was rechristened Endurance after the Shackleton family motto, ("By endurance we conquer"). The ship was originally projected ready by mid-May, but completion was delayed for a month.
Shackleton had the ship relocated from Norway to London. She arrived at the Millwall Dock in the spring of 1914, and Shackleton gathered equipment, stores, finances, and crew until the end of July. The 'tween deck was converted into a cargo hold, and the crew made their quarters in the forecastle. The darkroom remained, abaft of the boiler. The refit also saw the ship repainted from white and gilt to black. She retained the large five-pointed star on her stern that had referred to her original name.
Her new equipment included three ship's boats. Two were transom-built rowing cutters purchased secondhand from the whaling industry. The third was a double-ended rowing whaleboat built for the expedition to specifications drawn up by Frank Worsley, Endurances new captain. After her refit, Endurance began the short coastal journey to Plymouth on 1 August 1914, the day that Germany declared war on Russia.
To find crew for the Endurance, Shackleton reportedly placed an advertisement in The Times, reading:
Voyages to the Antarctic Circle in the 16 years prior to Endurances purchase had been almost uniformly successful with only one vessel, the 30-year-old whaler Antarctic, having been crushed in the ice. With it being felt that little harm could come to a purpose-built ship in a sea in which ice halted all waves, Endurance became the first ship to be insured for her journey. All previous examples had their insurance end at the last port of call before their journey into the ice. Lloyd's of London and the Indemnity Marine Insurance Company underwrote Endurance at the value of £15,000.
Voyage Embarking on her maiden voyage, Endurance sailed from Plymouth on 8 August 1914 and set course for Buenos Aires, Argentina, under Worsley's command. Shackleton remained in Britain, finalising the expedition's organization and attending to some last-minute fundraising. This was Endurances first major voyage following her completion and amounted to a shakedown voyage. Built for the ice, her hull was considered by many of her crew too rounded for the open ocean.
Shackleton took a steamer to Buenos Aires and caught up with his expedition a few days after Endurances arrival. On 26 October 1914, Endurance sailed from Buenos Aires to what would be her last port of call, the whaling station at Grytviken on the island of South Georgia, where she arrived on 5 November. She left Grytviken on 5 December 1914, heading for the southern regions of the Weddell Sea.
Two days after leaving South Georgia, Endurance encountered polar pack ice and progress slowed to a crawl. For weeks Endurance worked her way through the pack, averaging less than per day. By 15 January 1915, Endurance was within of her destination, Vahsel Bay. By the following morning, heavy pack ice was sighted and in the afternoon a gale developed. Under these conditions it was soon evident that progress could not be made, and Endurance took shelter under the lee of a large grounded iceberg. During the next two days, Endurance moved back and forth under the sheltering protection of the berg. On 18 January, the gale began to moderate and Endurance set the topsail with the engine at slow. The pack had blown away. Progress was made slowly, until hours later Endurance encountered the pack once more. It was decided to move forward and work through the pack, and at 5:00 pm Endurance entered it. This ice was different from what had been encountered before, and the ship was soon amongst thick but soft brash ice, and became beset. The gale increased in intensity and kept blowing for another six days from a northerly direction towards land. By 24 January, the wind had completely compressed the ice in the Weddell Sea against the land, leaving Endurance icebound as far as the eye could see in every direction. All that could be done was to wait for a southerly gale to start pushing in the other direction, which would decompress and open the ice.
In the early morning of 24 January, a wide crack appeared in the ice ahead of the ship. Initially across but long, by mid-morning the next day the break was over wide, giving the men on the Endurance hope that the ice was breaking up. But the break never reached the ship itself, and despite three hours under full sail and full speed on the engine, the ship did not budge. Over the next days, the crew waited for the southerly gale to release the pressure on the ice, but while the wind backed to the hoped-for south/southwest direction, it remained light and erratic. Unseasonably low temperatures of around additionally kept the ice together. Occasional breaks in the ice were spotted, but none reached the ship and all closed up within a few hours.
On 14 February, an open channel of water opened up ahead of the ship and dawn showed the Endurance was afloat in a pool of soft, young ice no more than thick, but the pool was surrounded by solid pack ice of in thickness, blocking the path to the open lead. A day's continual work by the crew saw them hack a clear channel long. This work continued through the following day (15 February) and, with steam raised, the Endurance was backed up within her pool as far as possible to allow the ship to ram her way through the channel. As the ship went astern for successive attempts, lines were attached from the bow to loosened blocks of ice, estimated to weigh 20 tons (18 tonnes), in order to clear the path. The pool proved too small for the ship to gain enough momentum to successfully ram her way clear and by the end of the day the ice began to freeze up again. By 3:00 pm, the Endurance had made of distance through the ice, with still to go to clear water. Shackleton decided that the consumption of coal and manpower, and the risk of damage to the ship, was too great and called a halt.
Drift
After this frustration, Endurances boilers were extinguished, committing the ship to drift with the ice until released naturally. On 17 February, the sun dipped below the horizon at midnight, showing the end of the Antarctic summer. On 24 February, regular watches on the ship were cancelled, with the Endurance now functioning as a shore station. The ship had slowly drifted south and at this point was within of the intended landing point at Vahsel Bay. But the icy terrain between the ship and the shore was too arduous to travel while carrying the materials and supplies needed for the overland expedition.