The Endurance was the three-masted barquentine in which Sir Ernest Shackleton sailed for the Antarctic on the 1914 Imperial Trans-Antarctic Expedition. She was launched in 1912 from Sandefjord in Norway and was crushed by ice, causing her to sink, three years later in the Weddell Sea off Antarctica.
Design and construction
Designed by Ole Aanderud Larsen, the Endurance was built at the Framnæs shipyard in Sandefjord, Norway and launched on December 17, 1912. She was built under the supervision of master wood shipbuilder Christian Jacobsen, who was renowned for insisting that his employees be experienced seafarers as well as skilled shipwrights.
Initially christened the Polaris (eponymous with Polaris, the North Star), Endurance was launched on December 17, 1912, 144 feet (43.9 m) long, with a 25 foot (7.6 m) beam and weight of 350 tons (356 metric tons). Though her black hull appeared similar to other vessels of a comparable size, her construction was designed for durability in polar conditions. Each joint and fitting cross-braced each other for maximum strength. Her keel members were four pieces of solid oak, one above the other, adding up to a thickness of 7 feet, 1 inch, while her sides were between 2 1/2 feet and 18 inches 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 two and one half feet thick, sheathed in greenheart, a notably strong and heavy wood. Her bow, where she would meet the ice head-on, had been given special attention. Each timber had been made from a single oak tree chosen for its shape so that its natural shape followed the curve of her design. When put together, these pieces had a thickness of 4 feet, 4 inches.
Shackleton looking overboard at the Endurance being crushed by the ice
Endurance final sinking November 1915Of her three masts, the forward one was square-rigged, while the after two carried fore and aft sails, like a schooner. As well as sails, Endurance had a 350 hp (260 kW) coal-fired steam engine capable of driving her at speeds up to 10.2 knots (19 km/h).
At her launch, Endurance was perhaps the strongest wooden ship ever built, with the possible exception of the Fram, the vessel used by Fridtjof Nansen and later by Roald Amundsen. The Fram was bowl-bottomed, which meant that if the ice closed in against her she would be squeezed up and out and not be subject to the pressure of the ice compressing around her. But since the Endurance was designed to operate in relatively loose pack ice, she was not constructed to rise out of pressure to any great extent.
Endurance was built for Adrien de Gerlache and Lars Christensen, who intended to use her to take tourists on polar cruises to hunt polar bears. Financial problems led to de Gerlache pulling out of the venture; Christensen sold the boat to Ernest Shackleton for GB£11,600 (approx US,000), less than cost. He is reported to have been happy to take the loss to further the plans of an explorer of Shackleton's stature. Shackleton re-christened the ship Endurance after his family motto, "Fortitudine vincimus" (By endurance we conquer).
Endurance left Plymouth, England on August 6, 1914, when it set course for Buenos Aires, Argentina, under the command of Captain Frank Worsley. Shackleton joined the ship later in Buenos Aires, with other crew members. The ocean crossing was Endurance's first major cruising since her completion and amounted to a shakedown cruise. The difficult trip across the Atlantic took more than two months. Built for the ice, her hull was considered by many of its crew too rounded for the open ocean.
On October 26, 1914 Endurance sailed from Buenos Aires to her last port of call, the Grytviken whaling station on the island of South Georgia off the southern tip of South America, where she arrived on November 5. She departed from Grytviken for her final voyage on December 5 towards the southern regions of the Weddell Sea.
Two days after leaving from South Georgia, Endurance encountered polar pack ice and progress slowed down. For weeks Endurance twisted and squirmed her way through the pack, averaging less than 30 miles per day. By January 15, 1915, Endurance was within 200 miles of its destination, Vahsel Bay. The following day, heavy pack ice was sighted in the morning and in the afternoon a blowing gale developed. Progress could not be made under these conditions, and Endurance took shelter under the lee of a large grounded berg. For the next two days, Endurance dodged back and forth under the sheltering protection of the berg.
On January 18, the gale began to moderate and Endurance, one day's sail from her destination, set the topsail with the engine at slow. The ice pack had blown away, and progress was made slowly until Endurance encountered the pack once more. Shackleton decided to move forward and work through the pack, and the Endurance entered the ice pack at 5:00 P.M.
The crew soon noted that this ice was different. The ship was soon beset by thick but soft ice floes, a soupy sea of mushy, brash ice. The gale regained intensity and blew for another six days from a northerly direction towards land. By January 24, the wind had completely compressed the ice in the whole Weddell Sea against the land - and around Endurance. All that could be done was to wait for a southerly gale that would decompress and open the ice in the other direction. Time passed, yet the ice remained unchanged.
Trapped in the ice, Endurance drifted in the Weddell Sea until her hull succumbed to the ice pack's relentless pressure on October 27, 1915. She finally sank bow first on November 21, 1915, the last ship of her kind.
Izak J H Hough
Member of The Nautical Research Guild