NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Why Not To Teach Running Fixes
From: Peter Hakel
Date: 2009 Dec 13, 18:58 -0800
Bowditch has a section on the running fix where LOPs are given by bearing lines and NAVAIDs. The running fix technique is also used to shift LOPs from multiple star sight to a common instant of time, thus accounting for the time elapsed between sextant shots. It seems to me that it is a good thing that it is still taught. Bill Buckley in his instruction video (made in the 1970s, I believe) states that 90% of celestial navigation on small boats is done with running fixes.
Peter Hakel
From: John Karl <jhkarl@att.net>
To: NavList <navlist@fer3.com>
Sent: Sun, December 13, 2009 6:15:07 PM
Subject: [NavList 11133] Re: Why Not To Teach Running Fixes
Peter,
No, I can't agree with your post #11122. A navigator always knows
something about where he is. The running fix ALWAYs assumes the
navigator knows the perpendicular distance between LOP1 and the
advanced LOP1 EXACTLY, and knows ABSOLUTELY NOTHING of his position
parallel to LOP1's orientation. Under what situation does this
occur??
Any newly acquired LOP, even of any orientation, should always improve
position knowledge of lesser accuracy.
JK
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From: Peter Hakel
Date: 2009 Dec 13, 18:58 -0800
OK, that makes things clearer for me.
I think that your question could be best answered by NavList members who, unlike me, have extensive knowledge of history of navigation. Perhaps in their studies of old logs they have come across a real-life and successful application of a running fix. Furthermore, not so long ago we debated the distortion of a noon-curve due to declination change and N/S motion of the vessel. I remember some postings where a connection with the running fix procedure was mentioned.
I believe that rules similar to natural selection also apply in science and technology. The one-body fix technique is not to be found in the literature because it has been tried and shown to be impractical. Conversely, my guess is that the running fix is included in the literature after all these years because it has proven its worth in the past.
I think that your question could be best answered by NavList members who, unlike me, have extensive knowledge of history of navigation. Perhaps in their studies of old logs they have come across a real-life and successful application of a running fix. Furthermore, not so long ago we debated the distortion of a noon-curve due to declination change and N/S motion of the vessel. I remember some postings where a connection with the running fix procedure was mentioned.
I believe that rules similar to natural selection also apply in science and technology. The one-body fix technique is not to be found in the literature because it has been tried and shown to be impractical. Conversely, my guess is that the running fix is included in the literature after all these years because it has proven its worth in the past.
Bowditch has a section on the running fix where LOPs are given by bearing lines and NAVAIDs. The running fix technique is also used to shift LOPs from multiple star sight to a common instant of time, thus accounting for the time elapsed between sextant shots. It seems to me that it is a good thing that it is still taught. Bill Buckley in his instruction video (made in the 1970s, I believe) states that 90% of celestial navigation on small boats is done with running fixes.
Peter Hakel
From: John Karl <jhkarl@att.net>
To: NavList <navlist@fer3.com>
Sent: Sun, December 13, 2009 6:15:07 PM
Subject: [NavList 11133] Re: Why Not To Teach Running Fixes
Peter,
No, I can't agree with your post #11122. A navigator always knows
something about where he is. The running fix ALWAYs assumes the
navigator knows the perpendicular distance between LOP1 and the
advanced LOP1 EXACTLY, and knows ABSOLUTELY NOTHING of his position
parallel to LOP1's orientation. Under what situation does this
occur??
Any newly acquired LOP, even of any orientation, should always improve
position knowledge of lesser accuracy.
JK
--
NavList message boards: www.fer3.com/arc
Or post by email to: NavList@fer3.com
To , email NavList+@fer3.com
NavList message boards: www.fer3.com/arc
Or post by email to: NavList@fer3.com
To , email NavList+@fer3.com