NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Brad Morris
Date: 2014 May 23, 20:21 -0400
The biggest problem Worsley had was glossed over in point 3.
They were on Elephant Island but in the sailing directions of the day, the longitude of Cape Belsham (on Elephant Island) is given. That's all well and good, but the charts of the day merely resemble Elephant Island. For Worsley to use this data, he had to know if they were located on Cape Belsham or if Cape Belsham was some other point on the Island. It is not as if there was some convenient sign post identifying it.
Consequently, after months marooned on the ice, Worsley set out from Elephant Island with an unknown relationship between his chronometer time and longitude. If he could have identified Cape Belsham, than he could have established the relationship between a published longitude and his chronometer. Alas, it was not to be.
There is one further wrinkle in this. I have managed to research various sailing directions, all published before 1914. There is no agreement among them as to the longitude of Cape Belsham. I am not aware of which charts or sailing direction Worsley had with him. So even if he could identify Cape Belsham, Worsley could have gone through the entire exercise and still have had an inaccurate relationship because the published data could have been wrong!
Brad
Good catch Orjan.
There must be a typo of some kind. At the equator 4 seconds of time equals 1' ( 1 nautical mile). For Worsley's the chronometer error seconds has to be multiplied by the cosine of the latitude then divided by four. That's about 0.6' per 4 seconds of time as I see it. I don't think there was much of a chronometer problem as long as the 11 minutes and 55 seconds was applied to the chronometer. Worsley would have surely done this.
Greg Rudzinski
Re: Frank Worsley's Sextant: the certificate
From: Örjan Sandström
Date: 2014 May 23, 16:10 -0700
Uhm. 5 seconds of time is closer to 1' then the 20' given in the document, but that is me speaking. as far ad i know the rule of thumb is 4 seconds to 1' so things seem switched around there.-
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