NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Navigation and whaling
From: George Huxtable
Date: 2009 Feb 20, 21:26 -0000
From: George Huxtable
Date: 2009 Feb 20, 21:26 -0000
Brad Morris wrote these intriguing words- "I will even offer up that exemplar of navigation, Frank Worsley, who navigated by time sights, on that famous sail from Elephant Island to South Georgia island in the 1900's. His account is offered in his book and in his navigation log book which lives in a museum. Was that appropriate 50 years after Sumner provided his method? Some would argue that it wouldn't meet the navigation standard of the day, yet it is hard to argue with success." ==================== Can Brad tell us more about that "navigation log book which lives in a museum", please? Which museum? Has it ever been made publicly available? Is it indeed legible, after all it's been through? I would love to discover more about that journey. Worsley's own account, in "Shackleton's Boat Journey" (1933; my edition is 1940), though thoroughly gripping, is frustratingly short on navigational detail, and he offers no maps at all. The same journey is described in similar words elsewhere; in Shackleton's "South" (1919; mine is 1983), with a few maps; in Worsley's "Endurance; an epic of polar adventure" (1931; mine is 1999), no maps; and in "Shackleton's Captain", a biography of Worsley, by John Thomson (1999), more (but still inadequate) mapping. For information on South Georgia today, I can thoroughly recommend "Antarctic Oasis" (1998), by Tim and Pauline Carr, who have thoroughly explored every nook and cranny in their 100-year-old 28ft. engineless wooden ketch, being also curators of the South Atlantic whaling museum there. The stunning photographs in this book are a delight. =================== Now for the navigation on that amazing journey from Elephant Island. As Brad says, it's hard to argue with success. But the voyage, and its navigation, were not entirely successful; if they had been, that perilous crossing of the island would not have been necessary, because the original intention had been to round the NW corner of South Georgia to reach a whaling station directly. But Worsley honestly admitted, when nearing the island, that he couldn't be sure of his position within 10 miles or so, and Shackleton then sensibly concluded that in that case, such an approach would run the risk of missing the island altogether, and being swept East past it. Worsley's difficulty with his Sun altitudes was partly the fleeting and indistinct appearances of the Sun, but far worse, the guesswork in determining the horizon, from so low down in such big seas. On the thirteenth day, Worsley tells us that he had so far been able to get the Sun only four times, two of these being mere snaps or guesses through slight rifts in the clouds. Yet, after each such observation, he presents us with a latitude and longitude, stated to the nearest arc-minute. How could he do that, when a single Sun sight can provide only a position line, so one can only obtain a longitude by assuming a latitude? Such positions must have been heavily reliant on the dead-reckoning. The most interesting reference to navigation was on the fourteenth day, 7 May 1916, when at 9:15 am the Sun's limb was clear, though the horizon was misty. He continues- "The lateness of the hour, and the misty horizon, made a poor observation for longitude. At noon, the Sun's limb was blurred by a thick haze, so I observed the centre for latitude. Error in latitude throws the longitude out, more so when the latter is observed, as now, too near noon." I would go along with Brad, in presuming that Worsley had gone back to navigational techniques of the previous century. He seems to be avoiding chart-based position lines by instead directly calculating his longitudes from a before-noon Sun observation, using an observed noon-Sun latitude. And we may guess why, when we read of conditions aboard the 22ft canvas-decked James Caird, when any paper had become sodden, and there was no vestige of any sort of chart-table. Not that the alternative, using printed tables, would have been easy either. The whole journey was a remarkable achievement for the six participants, for the James Caird, and not least for their Primus stove, which kept them alive, and was finally abandoned on the mountain descent into Grytviken, after the last of its fuel had gone. George. contact George Huxtable, at george@hux.me.uk or at +44 1865 820222 (from UK, 01865 820222) or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---