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Subject: SS Leg 82 Question 8a
From: Yourname Here (ffive@XXX.XXX)
Date: Tue Dec 04 2001 - 01:18:18 EST
'My apologies to all. I forgot to delete the answers from the posted
version
of Leg 82. Dan Hogan'
Excepting the answer for Q 8a
'8a) As an aside try calculating from the RFIX to Sydney (33d 50.0'S
151d 20.0'E)
So here is my answer:
RhumbLine Course= 225.9d Dist= 4507.5 nm
GC(Init) Course= 225.8d Dist= 4505.1 nm
Was mildly surprised that there was not more of a difference between
Rhumbline and GC courses. As a check worked it out for the opposite
trip. The distances were the same but the GC(Init) Course= 54.8d, the
opposite of which is 234.8d, which appeals more, if only because it is
more different.
Mercator and Mid-Latitude remain mysteries, for the moment at least.
Incidentally, know S33 50' E151 20' well, its about 2 miles to the east
of South Head, the entrance to Sydney Harbour. Go out there to practise
taking sights, its a convenient DR, although too close to the coastal
cliffs for sights to the west. You can't just sit there, even if the
prevailing fine weather NE winds are absent (they often calm down as it
gets dark) because of the south setting Eastern Australian Current.
Unlike the Gulf Stream, all anybody here seems to know or care is that
it flows at from 2 to 4 knots. I suspect that it is just as complex an
ocean river as the Gulf Stream. Know that its strength can vary greatly,
and that protruding headlands can send a weaker counter current flowing
to the north, close to the coast. It seems to be strongest along the 100
fathom line, 8-10 miles offshore, the edge of the continental shelf.
Many thanks to Dan Hogan and team for the SS series. Enjoy them greatly,
even when I can't achieve the same answers !
Peter Fogg
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