NavList:

Frank wrote:

"One thing
caught my eye. He speaks of "deduced reckoning ('ded' reckoning...not dead
reckoning)". Of course, I've heard this "corrective" etymology before, and
it may or may not be a real etymology, but what's interesting is that this
story is much more popular among people who learned air navigation before
marine navigation. It's an actual cultural difference between these two
schools of navigation. Does anyone know who made "ded" popular among flying
navigators? Given the strong influence of Weems on early air navigation, was
it him again? "


You can't blame this one on Weems, he doesn't mention this old chestnut in his books. (For that matter, where does "chestnut" come from?) Nor do Chichester, Mixter, Dutton, or Bowditch.

I thought, perhaps, it sneaked in from the Army Air Corps but it is not mentioned in TM 1-205, Technical Manual Air Navigation (1940), TM 1-206, Technical Manual Celestial Air Navigation (1941), nor in AFM 51-40, Air Navigation (1951.)

Your suspicions may still be correct. The first place I found this mentioned was in H.O 216, Aircraft Navigational Manual (1941.) "Dead reckoning, or the original expression, deduced reckoning, as the name implies, consists of determining the aircraft's location by means of estimating the true track and ground speed." (Interestingly, it is not found in the 1967 edition.)

The next mention I found was in The American Air Navigator,  Mattingly (1944.)  " The term 'Dead Reckoning' is commonly supposed to have evolved from 'Deduced Reckoning.' First, 'Ded. Reckoning' as an abbreviation, the form eventually became 'Dead Reckoning' for convenience."
Next in Air Navigation Supplement Prepared by the Bureau of Naval Personal to supplement Dutton's ninth edition (1948.) " The name is derived from the term "deduced reckoning'."

Finally in The American Flight Navigator, Dohm (1958.) "It is , in other words,literaly reckoning by deduction, which is where the name came from."

gl


frankreed@HistoricalAtlas.net wrote:

These are some news items I noticed this week through Google News. 

1)
There's a nice little article at allatsea.net by Peter Muilenberg about a 
visit years ago to Aves Island. He has a lament for the lost days of 
celestial:
"This was in the days before GPS, back when  navigation required a sextant 
and tables and art and judgment to determine where you were on the ocean. It 
was called celestial navigation and it was not something that anybody's dog 
could be trained to do. 

Something dear has been lost, like so much else in the  modern world which 
has stripped life of its subtleties and its mysteries by doing everything 
for us and rendering the art of navigation a matter of pressing a button on 
a plastic  magic card which also functions as a camera, a wristwatch, a 
computer and a washer/dryer. 

It certainly added to the mystique of the Captain's authority when he 
brought out the precious instrument, 'sextant,' like something whose 
mysterious power one had to handle gingerly lest it burn him, then peered 
through a tube to discern the future, then consulted with his numerologies 
and ciphers, then plotted lines and angles and arcane  arithmetics - all of 
which so baffled the uninitiated that they kept themselves well in check and 
particularly looked to the welfare of the Captain, at least well out of 
sight of land." 

The rest of the story is charming (nothing else about navigation). Read it 
here:
http://www.allatsea.net/specificissueeditorial.php?featureid=2011 

2)
Here's an article from New Delhi on dhows:
http://www.business-standard.com/india/storypage.php?autono=340174
There is apparently still some trade in the Indian Ocean carried by dhows, 
traditional wooden boats, formerly sailing vessels, now mostly 
diesel-powered. As the article notes with some surprise, much of this trade 
is with Somalia these days since no other merchant vessels will visit there. 

As for navigation,
"Sailing in these boats is inherently risky. The two seafarers associations 
say on average five to six boats are lost every year. But crew safety has 
improved due to the now-mandatory Global Positioning System (GPS) along with 
such safety gear as distress radios, life preservers and fire suppression 
equipment." 

But there are traditionalists, albeit retired, even in the Indian Ocean.
"It is a special trip to meet 76-year-old Shivji Bhuda Fofindi at Mandvi, as 
he is a rarity for two reasons. First, he is a Hindu sailor and second, he 
is among the last of a generation who used to pilot purely wind powered 
ships. Shivji, since retiring, has set up his own makeshift simulator to 
train young ship pilots. 

He says that a pilot is most crucial as the wooden hull doesn’t take kindly 
to scraping against the sea bottom. He recalls that the challenge was 
tougher when they had to dock in a headwind, testing the nerves of even the 
most experienced pilot. A stickler for the basics, he says there is one 
thing he enjoys drilling into his pupils — using the sextant. 'It is easy to 
use the compass. But navigators today are lost if the GPS battery dies. They 
are finished for good,' he laughs." 

3)
Here's an odd place to find the phrase "celestial navigation":
http://www.metalunderground.com/news/details.cfm?newsid=39976 

It's a brief account of a visit by "metal" musician Steve Morse to the 
cockpit and navigator's station aboard an old Tu-134, a sixties era Russian 
airliner which had a bomber-like glass nose for the navigator. One thing 
caught my eye. He speaks of "deduced reckoning ('ded' reckoning...not dead 
reckoning)". Of course, I've heard this "corrective" etymology before, and 
it may or may not be a real etymology, but what's interesting is that this 
story is much more popular among people who learned air navigation before 
marine navigation. It's an actual cultural difference between these two 
schools of navigation. Does anyone know who made "ded" popular among flying 
navigators? Given the strong influence of Weems on early air navigation, was 
it him again? 


 -FER
PS: I know I have some posts to answer from last week. I will try to get to 
them tomorrow. 





  

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