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    Re: How Worsley Navigated
    From: George Huxtable
    Date: 2009 Feb 26, 14:42 -0000

    Brad Morris wrote-
    
    "I would like to revise my speculation at this point.  South Georgia
    Island has a northern most point at Bird Island, around 54 deg 0'S.  The
    southernmost point of SGI is around 54 deg 50'S.  It appears as if
    George was right, they tried to sail directly to SGI from Elephant
    Island.  When they reached the appropriate mid-point of the latitude of
    SGI (54 deg 30'S), they found no island!  Gasp! Was it east or west?
    With Bird Island just over 38 degrees W, I speculate that they chose to
    steer east."
    
    ================
    
    Why on Earth does Brad feel the need to speculate about this? With respect,
    his speculation makes no sense at all. He simply has to read what Worsley
    wrote; has he done that?
    
    As I explained before, the original intention was to head Northeasterly to
    round the NW corner of South Georgia (Willis Islands, Bird Island, Cape
    North), all rugged rocks, to reach the inhabited whaling stations in inlets
    along the Northern coastline. To do that, the navigation had to be good
    enough to keep North of those hazards, yet to ensure sighting the land to
    avoid being blown Eastwards past it by the prevailing wind. To achieve that,
    reasonable visibility would be called for. Worsley considered his
    observations were good to only 10 miles or so, and Shackleton decided that
    wouldn't be sufficient accuracy. I reckon that was a seamanlike and
    pragmatic choice, even though the alternative was to change course Eastwards
    toward the unknown and uninhabited South coast, and then cross the mountains
    of the interior, as had never been done before.
    
    As Worsley's text and his map of the journey makes clear, that change of
    plan, and change of course, was made some days before South Georgia was
    expected to show up. Not at all as Brad surmised.
    
    ==================
    
    Let's try to clear up some other matters.
    
    Chronometers.
    
    Brad posted this-
    
    "I went back and present herein the two chronometers which claim to be the
    one used by Worsley.  Obviously, they both can't be right.
    
    This one is from the National Maritime Museum in Greenwich, England and is a
    Thomas Mercer boxed, gimbaled chronometer.
    http://www.nmm.ac.uk/server/show/conMediaFile.2279
    
    This one is from the James Caird Society, a pocket watch  type chronometer
    http://www.jamescairdsociety.com/shackleton-news.php?id=102901 "
    
    Brad is right to be sceptical. Worsley's testimony is clear; that he used a
    Smith chronometer, just as illustrated by the James Caird Society. Samuel
    Smith specialised in such pocket instruments, though also made standard
    gimballed ship-chronometers. The Smith name survived to modern times as
    Smith's Industries. That pocket-chronometer, intended for sledging parties,
    would have been more appropriate for the small-boat journey than a big
    mahogany box type.
    
    Worsley's words were, about the morning of the day on which they left
    Elephant Island-
     "Immediately after breakfast the Sun came out obligingly. The first sunny
    day with the horizon clear enough to get a sight reading for my
    chronometer.", with a footnote- " This English chronometer, an excellent one
    of Smith's, was the sole survivor, in good going order, of the twenty-four
    with which we set out in Endurance".
    
    So the Greenwich museum claim seems quite unjustified, and I will contact
    Richard Dunn at NMM to point that out.
    
    Moral: don't accept anything without questioning. Be sceptical about what
    anyone tells you; that includes what I tell you.
    
    =================
    
    The James Caird society's web page, that Brad referred to above, also shows
    Worsley perched on what is presumably the "lookout station" to take a Sun
    observation. That's one of Hurley's superb pictures, in "South" (but not,
    unfortunately, in my cheapo paperback edition, published by Century, which
    had been shorn of all plates and of Shackleton's fold-out map).
    
    That lookout station must have been constructed when the expedition was
    living on the ice, a mile and a half away from where Endurance sank. It
    would have given a view of approaching leads in the ice or other movements.
    It would also serve the purpose for which Worsley was using it, of providing
    an elevated viewpoint for measuring altitudes, that allowed a clear view of
    the distant ice-horizon, clear of local ridges and hummocks. That was
    important, because they needed to find out, from accurate celestial
    observations, the speed and drift-direction of the ice that trapped them.
    They needed that, to discover if that motion on its own would take them out
    of the ice-trap, or if they needed to set off across the ice to escape (it
    was the latter). That was also the purpose of the occultations, to determine
    any slow drift of their chronometers.
    
    The lookout must have provided an insecure perch when an Antarctic wind was
    blowing. One false step would have had serious consequences.
    
    That Hurley photo doesn't provide enough detail to show much about the
    sextant in use, but the glimpse of the scope that it affords looks like an
    immense night-glass, similar to the scope shown in the photo that Clive
    Sutherland enlarged in [7418]. That picture isn't in "South", from what I
    can tell, but appears in Roland Huntford's "Shackleton's voyages", which I
    don't have (yet). (That shouldn't be confused with the same author's
    biography of Shackleton, which I have.). The enormous telescope shown in
    that picture looks rather inappropriate for the Sun job in hand, and out of
    proportion with the area of the sextant's mirrors; it's a bit of a puzzle,
    to me. Contrary to Clive, the sextant shown in that picture looks to me to
    have a frame that differs from the one in the box, that Brad copied to us.
    Clive has told me that photo seems to relate to Shackleton's last voyage on
    "Quest", the expedition on which he diad, of a heart attack, at Grytviken in
    South Georgia.
    
    Brad, could you tell us a bit more about the touring exhibition, please? I
    am aware that Caird travels around the World a lot now, from her London home
    at Dulwich College (Shackleton's old school) who own her. Where was she when
    you visited? (Can you still call a vessel named "James Caird a "she", I
    wonder?).
    
    Some Caird exhibitions in the past have used a replica craft, not that I'm
    suggesting that here. I understand that one such exhibition was arranged
    some 10 years ago by the American Museum of Natural History (if I've got
    that right) with gee-whiz computer visuals, but a "replica" Caird.
    
    ==========================
    
    When Brad has done with contemplating the angle of his knob, we would
    welcome some information about the observations. Did Worsley provide time
    and altitude for each sighting, and give any details of his working, to
    arrive at his quoted lat and long? Or did he just provide the result?
    
    George.
    
    contact George Huxtable, at  george{at}hux.me.uk
    or at +44 1865 820222 (from UK, 01865 820222)
    or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.
    
    
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