Master Navigation Watches: A-9; A-13; 5740; and 5740-1

Dave Chaplain

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And one more Elgin 0-23 black dial example, with the movement marked:

B.W. Raymond 21 Jewels Adjusted 5 Positions Temperature U.S. Army A.C., E.N.W.Co. U.S.A. (under bal)

And with the case marked:

Type A13 Spec. No. AN-GG-W-108 Ser. No. AC42-4781 Mfrs. Part No. 1786 Ord. No. W535AC-2807 Elgin

View attachment 403634 View attachment 403635
On closer inspection the contract order number marked on the case for sn 40470553 has an additional numeral and the full case makings are:

TYPE A-13
SPEC. NO. AN-GG-W-108
SER. NO. AC42-4781
MFRS. PART NO. 1786
ORD. NO. W535AC-28071
ELGIN

And additionally, sn 40470707 is also in an A-13 style case with case markings:

TYPE A-13
SPEC. NO. AN-GG-W-108
SER. NO. AC42-2089
MFRS. PART NO. 1786
ORD. NO. W535AC-28071
ELGIN

The last numeral in the contract order number is nearly lost to the naked eye on both cases.
 

Jason Herron

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Hi everyone,
I just found out some very interesting information about the owner of the watch I had asked about in this thread. It belonged to Hank Dyminski, my wive’s grandmother’s second husband. He was a member of Jay Zeamer’s Eager Beavers and a crew member on the “Old 666”. If this watch is from that plane, then it is really something special but is there any way to tell if it is? Any help would be greatly appreciated.
Thanks
Jason
 

musicguy

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If this watch is from that plane, then it is really something special but is there any way to tell if it is?
I would say no, unless someone from a particular plane had the watch and documented it.
There would be no way to know.


Rob
 

Leigh Callaway

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So were watches like this issued to individuals or to an aircraft?
Thanks
Depends on the service, maybe even the type aircraft.

In his book "Time for America" (pp 107-108) Don Sauers describes a Hamilton 4992B SN 4C77991 which was issued to him personally for WWII service in the Pacific.

In the 1960s, Navy patrol squadrons kept the watches in the communications office and the watches were issued with cryptographic material just prior to a sortie. The watches - and the crypto - were returned to the comm office after the flight. The Comm Officer was responsible for the care and condition of the watches.
 

PapaLouies

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The A-13 was the first variant to include the "hack" feature into the stem. Pulling out on the stem stopped the movement. The A-13 has a white dial, with the minutes marked from 0-55 and the hours marked from 0-23. "GCT" is marked below the center of the dial. The hands are narrow, baton style. The case is smooth and slightly smaller than the cases used on the later variants. To the best of my limited knowledge, this watch was only manufactured by Elgin. A question to the members of this forum: Is anyone aware of any other manufacturer of the A-13 other than Elgin?
Hi Rob,
What about this!
 

musicguy

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Thanks PL I know(I've read it before), I can't explain the reason but my own Elgin A-13(and it could be an early one) has been
examined by me and a very competent watchmaker(who totally disassembled it) and there is no hack feature on
my watch.


Rob
 

PapaLouies

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Thanks PL I know(I've read it before), I can't explain the reason but my own Elgin A-13(and it could be an early one) has been
examined by me and a very competent watchmaker(who totally disassembled it) and there is no hack feature on
my watch.


Rob
Does it have a white dial?
 

musicguy

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No


Rob
 

C. N. Lloyd

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Just so everyone has this information on this thread:

Concerning the Elgin Master Navigation Watches, on the A13 case, Part No. 1767 is a white 0-23 dial. Part No. 1786 is a black 0-23 dial. Part No. 1790 indicates a black 1-24 dial, and the case will be marked AN 5740. Grtnev found the source documentation for this in 2017. Now, yours may not house the movement is it supposed to, but now you know what was in the case to begin with.

The Master Navigation Watch AN 5740 was part of the navigation kit that was used jointly by the Army and Navy, hence the AN designation. The A13 had been developed by the USAAC, and was more of a straight Army issue. Hamilton never made many, if any A13s; their entire WWII MNW production was the AN 5740. The watch itself was a component of the kit, which, like all of the other non-expendable components, had to be accounted for upon turn-in or when ordering replacement components. Other components of the kit would have included charts, pins, dividers, pencils, circular slide rules for airspeed and dead reckoning, a sextant or octant, and other watches like a Hamilton M23 chronograph, which mounted on the octant, and probably a couple of stop watches for fixed point navigation speed calculation, which also doubled for bomb time to impact calculations.

As the kit was generic, it is very unlikely that any particular kit or individual component could be traced to a particular airplane. All you would have would be the word of a particular user.

C. N. Lloyd
40 years of pocket watch collecting
 

musicguy

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Kent

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This looks like the same article posted by Robert Sweet on May 23, 2011, thanks for reposting it.
 
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PapaLouies

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Rob, does your G.C.T. BW Raymond have an un-cut balance wheel and a white metal hairspring?
Regards, PL
 

musicguy

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cut balance, the hairspring is silver colored(white metal yes)
bwraymond a-13.jpg


Rob
 

musicguy

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I do know that the Elgin invar type balance
were cut about 1/3 of the way around and not next to the
arm.


bwraymond a-13.jpg



EDIT here is another Elgin 581 with the cut in the same place.
1943 Elgin grade 581 model 15 24hr


Rob
 
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O2-71ranget

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The following three threads provide useful background.

https://mb.nawcc.org/showthread.php?30964-Army-Air-Corps-Center-Second-B-W-Raymond&highlight=master+navigation
https://mb.nawcc.org/showthread.php?100550-Hamilton-and-waltham-gct&highlight=master+navigation
https://mb.nawcc.org/showthread.php?136951-Elgin-A-13-Master-Navigation-Watch&highlight=AN5740

Summarizing the latter/post Weems development of the Master Navigation Watch which eventually evolved into the AN5740-1 variant:

The A-9 was the first variant that had a "hack" feature and was manufactured for the U.S. Army Air Corps by Longines. The hack feature was a slide bar at approximately the 2 o'clock position on the case. To the best of my limited knowledge, this watch was only manufactured by Longines. A question to the members of this forum: Is anyone aware of any other manufacturer of the A-9 other than Longines?

The A-13 was the first variant to include the "hack" feature into the stem. Pulling out on the stem stopped the movement. The A-13 has a white dial, with the minutes marked from 0-55 and the hours marked from 0-23. "GCT" is marked below the center of the dial. The hands are narrow, baton style. The case is smooth and slightly smaller than the cases used on the later variants. To the best of my limited knowledge, this watch was only manufactured by Elgin. A question to the members of this forum: Is anyone aware of any other manufacturer of the A-13 other than Elgin?

The AN5740 variant utilized a slightly larger case with knurling on the outside edge of the case. (Consequently the back case cover from an AN5740 will not fit the earlier A-13 case and vice versa.) Functionally, the AN5740 was essentially identical to the A-13 except that it incorporated a black dial instead of the white dial used on the A-13. Additionally, the "AN" designated that the watch was to be jointly use by both the Army and Navy. To the best of my limited knowledge, this watch was only manufactured by Elgin. A question to the members of this forum: Is anyone aware of any other manufacturer of the AN5740 other than Elgin?

The AN5740-1 variant was similar to its predecessor, the AN5740, in that it also incorporated the black 24 hour dial with the following changes:
1. The minutes were marked from 5-60
2. The hours marked from 1-24.
3. "GCT" is marked above the center of the dial.
4. The hands were changed to a larger RR spade style.

The AN5740-1 was manufactured by Hamilton (140,000 watches), Elgin (20,000 watches), and Waltham (5,000 watches).

The following pictures illustrate the dial/hand variations from the A-13 (left) to the AN5740 (center) to the AN5740-1 (right). The attached Excel spreadsheet lists 7 Elgin watches that I have found on this forum which cover the A-13 through AN5740-1 variants. What is interesting in this very limited amount of data is that the earlier serial numbers also carried the marking on the movement of "U. S. Army A. C.". Additionally some of these Elgin movements were gold flashed while others were not.

The development of the master navigation watch has been an interest of mine. I have owned both a Hamilton and Elgin 5740-1 for some time. Earlier this year, I was lucky enough to acquire an Elgin A-13. Just this past week, I acquired an Elgin AN5740. Although as a rule, I limit my watch collection to American RR and Military variants, if I could ever find a Longines A-9, I would definitely have to try and add it to the collection.

Also, I should mention, that in the picture of the A-13 example below, it has a very unusual additional feature in that there are two hour hands, 6 hours apart, for tracking two time zones. This feature was discussed in the last link listed above. This is the only master navigation watch that I have come across that had two hour hands.

Richard

View attachment 326291 View attachment 326292 View attachment 326293
Thank you very much
 

Jim Haney

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Another Elgin 581 Military, looks like from the Last run. Serial # 42078228. The plate is not stamped like most of these watches?
The Balance is not Invar, the cut is at the arm.

Elgin Data Base (Wayne Schlitt's) says that 20,080 of these grade 581 were made, however we don't know if all were Military and some have Gold Flashed movements?

DSCN5258.JPG DSCN5257.JPG DSCN5256.JPG DSCN5255.JPG
 

Alex_l

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Hi guys,

I'm currently trying to figure what model I got and from my understanding after reading this thread it seems to be a A-9. Btw this thread is a mine of information! That's awesome

Here is some pictures, if anyone would be able to confirm.

Many thanks

20220912_175118.jpg 20220912_175128.jpg 20220912_175237.jpg 20220912_175251.jpg 20220912_175306.jpg 20220912_175331.jpg 20220912_175326.jpg
 

Jim Haney

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Alex.
Welcome to the NAWCC Forums.... :)

Can you take a Pic of the movement and from back of the case I do not see any Military contract numbers.

It looks like a wind indicator with a slide switch for possibly a early Hacking feature ?

Thanks
 

Alex_l

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Alex.
Welcome to the NAWCC Forums.... :)

Can you take a Pic of the movement and from back of the case I do not see any Military contract numbers.

It looks like a wind indicator with a slide switch for possibly a early Hacking feature ?

Thanks
Hi Jim!

I've try to open it to see the movement, but it doesnt move (try to unscrew the back as i've seen on youtube) at all it my fingers and i definitely dont want to damage it with tools that I have on hand.
For military contract numbers, there is nothing written on the case or on the watch...

So basically I'm kind of lost on how to open it and dont see any other information more that what you see on the pictures i've posted
 

Jim Haney

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Alex,
Hard to speculate, it could be pry off back & bezel.. ? But I do not recommend trying that that unless you can see a pry slot..
 

grtnev

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Hi guys,

I'm currently trying to figure what model I got and from my understanding after reading this thread it seems to be a A-9.
Hello Alex,

First of all, let me also offer my welcome to the forum.

As Jim suggested, it would tell us a lot if you can get some pictures of the movement - the key point being was it made by Longines.

If you can’t get the case open, you might consider taking it to a reputable jeweler/watchmaker to see if they can open it.

When handling the watch I’d STRONGLY RECOMMEND that you have a strap or string looped through the case bow and the other end wrapped around your finger so it doesn’t slip out of your hand.

You have what appears to be a very special, early, (pre-WW2) A-9 master navigation pocket watch, with a wind indicator and hacking feature, manufactured by Longines for the U.S. Army Air Corps. Getting a look at/pictures of the movement will verify this for sure.

Does it run? If so does moving the slide bar at the 2 o’clock position stop the center seconds sweep hand?

Is the watch a family piece? Do you know it’s history?

The link below may provide some additional information for you. The pictures and description in this link are for a watch which appears to be the same as yours. A picture of the movement is included.

Richard
 
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Leigh Callaway

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The link below may provide some additional information for you. The pictures and description in this link are for a watch which appears to be the same as yours. A picture of the movement is included.

Richard
Another example in post number 2 here: Two Examples Longines Caliber 21.29 – 1919 and 1943 | NAWCC Forums
 

musicguy

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Alex I would like to add my welcome to the ones above, nice watch!


Rob
 
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Alex_l

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Hello Alex,

First of all, let me also offer my welcome to the forum.

As Jim suggested, it would tell us a lot if you can get some pictures of the movement - the key point being was it made by Longines.

If you can’t get the case open, you might consider taking it to a reputable jeweler/watchmaker to see if they can open it.

When handling the watch I’d STRONGLY RECOMMEND that you have a strap or string looped through the case bow and the other end wrapped around your finger so it doesn’t slip out of your hand.

You have what appears to be a very special, early, (pre-WW2) A-9 master navigation pocket watch, with a wind indicator and hacking feature, manufactured by Longines for the U.S. Army Air Corps. Getting a look at/pictures of the movement will verify this for sure.

Does it run? If so does moving the slide bar at the 2 o’clock position stop the center seconds sweep hand?

Is the watch a family piece? Do you know it’s history?

The link below may provide some additional information for you. The pictures and description in this link are for a watch which appears to be the same as yours. A picture of the movement is included.

Richard

So here are some answers

Yes it run perfectly and keep times like it should.
That piece was to my dad (born in 1935 and still alive). I don't know where did he got it, but i'll try to investigate the matter haha.
It's been in display in my house since I got it about 10 years ago without knowing anything about it. And this week, I've seen on the internet a pocket watch pretty similar to it and made me curious about mine and here I am talkingto you guys :)

I'm actually looking for a reputable jeweler/watchmaker in my area (near Montreal, Quebec, Canada)
I,ll keep you posted on the discovery about it's story and about what the jeweler will say about it and post picture of the movement!

You already been a great help to me
 
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grtnev

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That piece was to my dad (born in 1935 and still alive). I don't know where did he got it, but i'll try to investigate the matter .
Please do - discuss the watch with your Dad and document its history in writing - you’ll be glad you did.

Richard
 

Alex_l

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So the story ended pretty quick haha
he bought it out of an auction from the gouvernment of Canada at one time in his life haha

i'll post picture as soon as I found someone to open it
 

Alex_l

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So I can confirm it is a A-9 and from what the watchmaker told me, the inside is in super great condition and didn't been used a lot!

Here are the photos from the inside.

Next step for me would be to try to discover what year that watch been made. I guess I'll wrote directly to longines or maybe you have other ways to find that information?

Alex

received_3322039334789731.jpeg received_781572806328831.jpeg received_441807957763587.jpeg
 

Leigh Callaway

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