NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Averaging sights on commercial vessels
From: Trevor Kenchington
Date: 2004 Oct 7, 21:22 +0000
From: Trevor Kenchington
Date: 2004 Oct 7, 21:22 +0000
Alexandre, Stacy has given a better date for the introduction of SatNav than I could have done. (I suspect that I first encountered a receiver in about 1979. It was certainly not new technology for the ship's officers at that point.) As to other ocean navigation systems: LORAN-C has a range of a few hundred miles from the transmitters, which are necessarily on land. The range at night, using skywaves, is often longer than by day. I think LORAN-A had a longer range though much lower precision. There were other systems of similar vintage and similar range to LORAN-A: CONSOL for one. (Back in the 1970s, I sailed with yachtsmen who used CONSOL for navigation off the English coast. It didn't need any receiver more sophisticated than an ordinary AM transistor radio.) All of those systems had their origins in aids to wartime (1939-45) air navigation. To the best of my knowledge, the only civilian non-statellite electronic navigation system which could reach to mid-ocean was Omega, which was relatively low precision (though maybe not much worse than celestial). I have never seen an Omega receiver, and only once an Omega lattice chart, and I don't know how widely it was ever used. The system was either in place by 1975 or was being constructed then. (What other systems the military had, or the Soviet Bloc had, I do not know.) There was, of course, RDF which could provide mid-ocean radio bearings by the 1940s and maybe much earlier. I think its precision was well below that of celestial. None of which concerns the proper theme of NAVIGATION-L, except as markers for the decline of celestial methods in everyday use. Trevor Kenchington You wrote: > Trevor, > Thank you very much for your explanation. > I forgot about Sat Nav indeed. > Do you know when approximately did they start using it? > (I suppose, not earlier than late 70-s). > The manuals I cited were written in the 60-s when > no Sat Nav existed. > I am just trying to understand when CelNav was replaced > by various satellite-based systems as a main tool of finding > position on commercial and navy ships. > Alex. > > P.S. LORAN only works near a shore, correct? > The only precise means available in the middle of an ocean > are CelNav and satellite-based systems, correct? > A -- Trevor J. Kenchington PhD Gadus@iStar.ca Gadus Associates, Office(902) 889-9250 R.R.#1, Musquodoboit Harbour, Fax (902) 889-9251 Nova Scotia B0J 2L0, CANADA Home (902) 889-3555 Science Serving the Fisheries http://home.istar.ca/~gadus