NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Published, Shackleton and Worsley, Journey to South Georgia Island
From: Brad Morris
Date: 2018 Dec 25, 14:52 -0500
From: Brad Morris
Date: 2018 Dec 25, 14:52 -0500
Robin
Quite the interesting read!
Lars and you conclude that the wreck is somewhere in a box 4-5nm by 6nm. That's 30 square nautical miles to search.
Its debatable as to which size, as you and Lars note, due the uncertainties of the chronometers and anomalous refraction. A more logical size, given the uncertainty would be 10×10 nm or 100 square nautical miles.
Typical search patterns for ship wrecks involve traversing that box back and forth, such that the side band sonar can pick the wreck out from the bottom. Anyone who has even peripherally looked at the search for MH370 will understand how difficult the search for Endurance will be. Its in 3000m (~1.9 miles) deep water, with a relatively unknown bottom. There has been a century of sediment accumulation from the material carried off the continent by the ice. That will eventually bury the Endurance.
In my estimation, it will be pure luck if the instant expedition finds the Endurance. They certainly won't be carrying out a grid search, even if they wanted to, as the possible presence pack ice on the surface will inhibit it. They will keep an eye out, I'm sure, but it is not the primary focus.
Brad
On Tue, Dec 25, 2018, 2:30 PM Robin Stuart <NoReply_Stuart@fer3.com wrote:
Mike,
Thank you for passing on our papers. Neither of them however directly addresses the question of the location of the wreck of Endurance. This was examined in detail in a separate paper by Lars Bergman and myself that was published in the Journal of Navigation earlier this year. Some background can be found at http://fer3.com/arc/m2.aspx/Spur-moment-long-chron-Stuart-dec-2018-g43681. I made the paper available to the expedition leader, Prof. Julian Dowdeswell, who informed me that they were aware of it.
We find that a number of factors make the position much more uncertain than had been anticipated but we can be quite sure it's not at 68°39'30"S 52°26'30"W where the log places it!
Robin Stuart
