A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: 'Intentional Error' Method of Navigating to Destination.
From: Gary LaPook
Date: 2009 Nov 11, 01:44 -0800
From: Gary LaPook
Date: 2009 Nov 11, 01:44 -0800
Douglas wrote: "It is a curious co-incidence that Gatty's flight in Siberia mentioned in his book using this 'deliberate offset course to destination' method was in 1931; and so was Francis Chichester's flight across the Tasman Sea in 1931, (described in his book first published in 1964 - so Gatty is the first to describe it in print in 1957)." ------------------------------------------------------------------------------------------ Chichester first published "Seaplane Solo" in 1933 describing the technique. Coutinho published his description in 1922 and also presented it to the Pope! It received much coverage in Portugal where his name is well known as a national hero, following in the footsteps of Vasco Da Gama and other Portuguese navigators. Both Coutinho and Chichester used celestial LOPs which is different from the method described by Gatty. (BTW, I have Gatty's "The Raft Book" which is very interesting and describes several emergency navigation methods.) But the use of celestial LOPs with a deliberate offset to find a landfall is nothing revolutionary since the technique had been use for centuries. In the olden days, before accurate time was available, the only LOP available ran east and west establishing a latitude at noon. Sailors would aim off to the the east or to the west of their destination and then establish that they had intercepted the LOP (the parallel of latitude) by a noon observation and then sail east, or west, following the LOP to the landfall, a method known as "latitude sailing." gl email@example.com wrote: > Further to the Harold Gatty / Sir Francis Chichester comments:- > > I have found Gatty's book, and intended to scan the relevant bit but both the scanners I have will not function. There is something wrong with Mr. Gate's hated Microscoft XP operating system in my ancient computer so that it cannot find the TWAIN drivers. It's time to consider an Apple Mac as replacement. > ========= > > The mention of the 'intentional error' method is on page 70 of Harold Gatty's book "Nature is your Guide", where he mentions using it, (written in 1957). > > It is a curious co-incidence that Gatty's flight in Siberia mentioned in his book using this 'deliberate offset course to destination' method was in 1931; and so was Francis Chichester's flight across the Tasman Sea in 1931, (described in his book first published in 1964 - so Gatty is the first to describe it in print in 1957). > > I suspect the method was a well-known 'trick' discussed at the time in navigating circles of these pioneers of aerial navigation. > ---- > > I'll quote the relevant portion of Gatty's book:- > > " .... there is an additional means of straight-line navigating that is worthy of mentioning here - the method of the intentional error, the method of aiming (when the conditions of the journey permit) somewhat askew of the final target. > > I can recall from my flying days a successful use of this simple trick. I employed it on my world flight with Wiley Post in 1931, when we were in an area in which there were no distinguishable features to relate to the map. The area was Eastern Siberia; and we left Irkutsk for a 'leg' of some 1100 miles with the intention of refuelling at a small airfield on the bank of the Amur river. > > The last several hundred miles of this leg were over Northern Muncuria - over high grass country with no towns, no roads - indeed precious few distinctive features of any sort. We knew that we were unlikely to land much before dusk and that the airfield was not lighted. We could not afford to waste any time looking for it. I purposely set a course to hit the Amur river ten miles to the left of our destination. When we reached the river I told Wiley Post to turn right. We rounded a bend and there lay the airport. We made our landing with just enough light. Wiley Post could not understand why I was so definite about to turning to the right until later I explained it to him. > > There has been no check points for the last part of our route; and our maps were very questionable. If we had set a course directly to the field and had missed it when we reached the Amur river, we could have used up all our daylight by turning in the wrong direction...... > > ..... this shows the the value of the calculated intentional error - a simple method which can bring the traveler to the base line of his desired goal in no doubt whatever (unless he has been guilty of a really gross miscalculation) as to which way to turn. Any normal unconscious deviation is swallowed up in this intentional margin; by purposely aiming for a point either to the right or to the left of his objective, the navigator eliminates this uncertainty and is sure of his homefall. " > > ---------- > > Douglas Denny. > Chichester. England. > > > > > > --~--~---------~--~----~------------~-------~--~----~ NavList message boards: www.fer3.com/arc Or post by email to: NavList@fer3.com To unsubscribe, email NavListfirstname.lastname@example.org -~----------~----~----~----~------~----~------~--~---