A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Robin Stuart
Date: 2019 Oct 31, 08:52 -0700
Navigation on Shackleton’s voyage to Antarctica (Bergman and Stuart) has just been posted by the Canterbury Museum https://www.canterburymuseum.com/assets/DownloadFiles/Navigation-on-Shackletons-voyage-to-Antarctica.pdf This is the final installment in a trilogy of papers analyzing Captain Frank Worsley’s log and workbooks from Shackleton’s Imperial Trans-Antarctic Expedition of 1914. It looks at the navigation and day-to-day ship’s management from the departure from London’s India Docks on 1 August up to their entrapment in the Antarctic ice floes in January of 1915. It describes the various navigational methods and practices that were used on the voyage including longitude by sounding and position by double altitude using A.C. Johnson’s method. We also see Worsley’s Mercator sailing calculations and learn that he took his time sights very close to the prime vertical.
This paper closes out an investigation started 10 years ago initially involving Brad Morris, George Huxtable, Lars Bergman. I am a relative latecomer to the group. Along the way Henry Halbroth and David Castle provided key insights and information. We are all grateful to them for their assistance.
Two earlier papers have also appeared in Records of the Canterbury Museum 2018
Navigation of the Shackleton Expedition on the Weddell Sea pack ice (Berman and Stuart) https://www.canterburymuseum.com/assets/DownloadFiles/Navigation-of-the-Shackleton-Expedition-on-the-Weddell-Sea-pack-ice.pdf describes the observations made while trapped in the ice including the star sights during the polar winter and occultation timings needed to rate the chronometers. It also covers the period spent camped on the ice and boat journey to Elephant Island.
Navigation of the James Caird on the Shackleton Expedition (Berman, Huxtable, Morris and Stuart) https://www.canterburymuseum.com/assets/DownloadFiles/Navigation-of-the-James-Caird-on-the-Shackleton-Expedition.pdf studies the navigation from Elephant Island to South George. It contains images of the original log pages along with a transcript and replication of the calculations contained therein. It provides answers to some vexing and longstanding questions such as what source did Worsley use for the position of Elephant Island and just how did he rate the chronometers before departure. In looking into these questions, it was noticed that the US Chart 29104 contained errors. (see http://fer3.com/arc/m2.aspx/Cape-Belsham-Point-Wild-relocated-Chart-29104-Stuart-mar-2017-g38689 and http://fer3.com/arc/m2.aspx/Cape-Belsham-Point-Wild-relocated-Chart-29104-Stuart-jun-2017-g39375 ). I brought this to the attention of the National Geospatial-Intelligence Agency who are responsible for the chart. After due diligence and requesting imagery they issued 2 Notices to Mariners.
This work also spawned a number of spinoffs. Upon learning that a search using Autonomous Underwater Vehicles (AUV) was to launched for Endurance in February of 2019, Lars Bergman and I studied the log and determined that the position given was subject to uncertainties of several nautical miles in both latitude and longitude. Our conclusions are published in the Journal of Navigation and is viewable at https://www.cambridge.org/core/journals/journal-of-navigation/article/on-the-location-of-shackletons-vessel-endurance/5F1AD80B3445C2653F1C24EAD4B7460D/share/af04c02d4ebde51ac7addc3ea1fc34026f1a589c The article’s abstract was highlighted in the November-December 2018 edition of Navigation News which is an internal publication for members of the Royal Institute of Navigation. In the event the expedition lost its AUV and the search was abandoned. We will have to wait for future searches to be vindicated.
Lars Bergman, Brad Morris and myself were co-authors on the cover article in the May-June 2019 edition of Navigation News which discusses Worsley’s navigation on the expedition. The project generated a news release by the Canterbury Museum https://www.canterburymuseum.com/about-us/media-releases/researchers-use-museum-logbook-to-chart-extraordinary-voyage-of-endurance-lifeboat/ and garnered the attention of the James Caird Society http://www.jamescairdsociety.com/about/news/