NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
SS Leg 82 Question 8a
From: Peter Fogg
Date: 2001 Dec 03, 11:18 PM
From: Peter Fogg
Date: 2001 Dec 03, 11:18 PM
'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