The GMT-Master 16700.....A Forgotten Reference

[Tools]

When Pan-Am first commissioned Rolex to develop a two timezone watch for the new Boeing 707 jets in 1956 , their concern was to keep the pilots reference to home time intact, while still allowing them to track the different time zones they travelled through. It was felt that keeping a home-time reference would alleviate jet-lag as the pilots could still keep their circadian routine. This also gave Jet Navigators an in-cockpit GMT time reference necessary for Celestial Navigation of the era.

Their efforts resulted in the GMT-Master ref. 6542. The GMT stood for Greenwich Mean Time, which was the world standard for a unified or universal time clock.

It's use in practice was initially envisioned as having the watch set for local time, and the bezel was rotated to the new timezone... Local was read at the dial and the timezone you were presently in would be displayed in 24hr time on the bezel....simple. When you got back home the bezel triangle should be back at the 12 o'clock position.

The New GMT and it's line soon became the "standard" and a pilots must-have time-piece. NASA test pilots were given GMT-Masters during development of the record breaking X-series jet aircraft, and they were the personal time-piece of many American astronauts.

The ref 16700 that was produced from about 1988 until 1999 was the last of those watches with synchronized 24hr and 12 hour hands, but with the upgraded sapphire crystal, hacking seconds, and quick-set date.

Specifications
Model: .........................GMT-Master
Reference Number: ........16700
Production Years: ..........1988-1999
Movement: ...................Caliber 3175
Power Reserve: .............48 Hours
Water Resistance: .........100m
Bezel:.......................... Bidirectional
Crown: ........................Screwdown Twinlock
Crystal:....................... Sapphire
Diameter: ....................40mm
Thickness: ...................N/A
Weight: .......................123 grams
Bracelet: .....................Steel, Oyster or Jubilee
Lug Width: ..................20mm
Watchwinder Direction: ..Both


From my personal collection, a 1997 T series GMT 16700:
GMTM Face.jpg

One of the last of the tritium dials:
GMT Tritium.jpg

Lug holes case....a treat for the eyes:
GMT LugHoles.jpg

There are no numbers here....this is one of the originals:
GMT MasterFont.jpg

The GMT 16700 came equipped with the 28,800bph ca 3175 movement:
GMT3175a.jpg
This movement features a full balance bridge for stability and accuracy, one of Rolex trademarks.. You can see the KIF shock spring at the balance pivot jewel:
GMT3175e copy.jpg

A 24 hour hand that travels around the dial exactly one half the speed of the main hour hand:
The bezel is turned to the number of hours you are from local time to track any other time-zone in 24hr time, provided you have set your watch to local.

Here is an excerpt from the GMT 16700 Owners Manual:
GMT Book1.jpg
GMT Book2.jpg
GMT Book3.jpg
GMT Book4.jpg

While flying and controlling in Alaska I would set the bezel at -8 hrs to keep track of GMT time, a useful reference for pilots.
GMT AlaskaBezel.jpg

One unusual aspect of the 16700 - It was offered with the 93150 Sub Style bracelet (perhaps to fit over a flight suit?), a popular option which I preferred at the time:
This one still has the original 93150/501B bracelet - V9, Sept 1996 clasp code...Purchased in early 1997:
GMT 93150.jpg

This was the last of it's kind, almost ignored because of the new 16710 and only a few of them were made:
GMT Omni.jpg

[glocati]

Great write up and pics, Larry. I love my 16700 !

[karmatp]

Great post Larry, thanks.

[Duc-904]

Good stuff Larry! I recently picked up up one of these gems and can't keep it off my wrist!

[jdc]

Great write up and pictures, thanks

[mike]

Excellent review Larry. The 16700 holds a special place in the heritage of the GMT....one that collectors are starting to take notice of.

Stunning example.

[redshirt1957]

I know what you mean.

[glocati]

Originally Posted by Duc-904

Good stuff Larry! I recently picked up up one of these gems and can't keep it off my wrist!

Glad to see another 16700 wearer in Portland !

[seantk]

Good write up and history

Sean

[Duc-904]

Originally Posted by glocati

Glad to see another 16700 wearer in Portland !

Likewise!

[ROA]

very well put!!!

[pwrslider]

Originally Posted by seantk

Good write up and history

Sean

Very cool stuff!!!

[Lol-x]

Very interesting Larry, thanks for sharing those great photos and the story

I really like the movement photos

[Tools]

Originally Posted by I_WANT_YOU

Correct me if I am wrong, but didn't Rolex attempt to send watches into space that later couldn't hack it somehow. Wasn't it an Omega that ultimately became the official watch.

A story I take ZERO pleasure in relaying, since we all know Omega is a Rolex cover band.

Well...That's not exactly the case..

NASA bought several different brands, including Rolex, back in the early 60's, and put them through a series of torture tests. The winner of these tests, and the "official" watch to be used for space walks was the Omega Speedmaster.

Astronauts can use practically any other watch they want while in space, except for official outside-the-shuttle walks, and many of them do wear a Rolex..

[jm433]

One thing I've often wondered about is why the two-colored bezels? I'm assuming the idea was to separate day from night at a glance, but never thought this made much sense. Daylight doesn't necessarily correspond to 6 am to 6pm and the use of military-time hour indicators on the bezel already indicates a.m. versus p.m. at a glance.

Was the two-colored bezel just for decoration? You've shown your black bezel model and I don't think you lose any functionality with that....

[Tools]

Originally Posted by jm433

One thing I've often wondered about is why the two-colored bezels? I'm assuming the idea was to separate day from night at a glance, but never thought this made much sense. Daylight doesn't necessarily correspond to 6 am to 6pm and the use of military-time hour indicators on the bezel already indicates a.m. versus p.m. at a glance.

Was the two-colored bezel just for decoration? You've shown your black bezel model and I don't think you lose any functionality with that....

This has been the topic of conversation...some of it heated, over the years..

The original ref 6542, which had a very short life was navy over red. Keeping in mind that this was a pilots watch, the design is similar to an artificial horizon instrument, probably the main instrument used by pilots.

The color quickly became the familiar "pepsi" dial within a few years. Now, at the time Pan-American colors were bright blue and silver or white, depending on if you were looking at the airplane or the uniform, and red/white/blue was uniquely American, so blue over red seems a natural..

It does provide a quick reference when looking at it as the 6 am to 6pm area is generally daylight and it is red, whereas, the 6 pm to 6 am time is evening/dark and the bezel is black/blue in this area. (another theory for the colors)

The functionality of the black bezel is the same, but I do notice a difference in "hunting" for the 24 hour hand without the two colors..

[jm433]

Interesting that the first reference model was black over red. I had always assumed that the pepsi bezel was the first. I guess its just the most iconic.

[jm433]

After having had my GMT 16710 for a few months, I think I might give up the independent hour hand for the quickset date of the 16700. It's kind of a pain to set the date without the quickset feature. And I have been wearing mine with the hour hand and 24-hr hand synchronized anyway. I rotate the bezel for the second time zone.

[Leighton]

Originally Posted by jm433

After having had my GMT 16710 for a few months, I think I might give up the independent hour hand for the quickset date of the 16700. It's kind of a pain to set the date without the quickset feature. And I have been wearing mine with the hour hand and 24-hr hand synchronized anyway. I rotate the bezel for the second time zone.

I can see your point, but for me with the international travel I do, nothing is cooler than pulling the crown out to position 2 and turning it to your destination time zone while the watch continues to tick on!

[Z-Sub]

Excellent Review.

[what3ver]

Originally Posted by I_WANT_YOU

since we all know Omega is a Rolex cover band.

Ouch. I wouldn't say that, considering Omega has existed almost twice as long as Rolex for one. I actually own more Omega's than Rolex's, and I assure the price difference has nothing to do with it.

[DSJ]

Great review. I hope to have a GMT Master (or II) some day.

[jtrader]

I love the look of the GMT with the all black bezel. In fact if I would have bought mine with an all black bezel if I could have. But my only option at the time was the Coke with the new 3186 or a pepsi with the 3185. So I decided to go with the 3186.

Does anyone know how I might get my hands on a black bezel. I understand that there prob no longer being made since Rolex came out with the new ceramic bezel's.... Is this something that I would half to send in threw my AD to have done, or would I be able to find an AD that would order one for me?

Any advise would be great as I am wanting to expand my options with this timepeice!!

[Dan Pierce]

Great read, Larry. I'd love to own a 16700 someday. Very interesting about the [Sub] bracelet used for a while.
Thanks for sharing.
dP

[redshirt1957]

Originally Posted by Dan Pierce

Great read, Larry. I'd love to own a 16700 someday. Very interesting about the [Sub] bracelet used for a while.
Thanks for sharing.
dP

Yep, I was lucky to get one with the original Sub bracelet. Makes it kind of unique.

[Dan Pierce]

Originally Posted by redshirt1957

Yep, I was lucky to get one with the original Sub bracelet. Makes it kind of unique.

Very cool, Joe!
dP

[FrankinCA]

I like reading this historical information about how the watch came about.

best,

Frank

[lordcon]

I find it interesting that the Rolex instruction manual refers to the watch as a "GMT Master I" as opposed to just "GMT Master". The "I" implies that there is a "II"? somewhere amist?

[etp095]

great looking watches,you guys have there.

[JimC]

Excellent review and photos! I've been searching for a GMT (not sure which one) and this thread provided me with a wealth of information. Really useful to see how it works, plus the explanation right from the manual. Wasn't sure of the differences between the GMT I and II; this review and the comments said it all.

Thanks!