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The History of the GMT Watch Complication

Rolex GMT Master 1955 Rolex GMT Master II 1982

Left to right: Rolex GMT Master (1955) and GMT Master II (1982)

Horological complications were born out of necessity, at a time when mechanical watch or clock-making offered a portable and fairly accurate solution to the problem at hand, whether that was the need to time a horse race, in the case of the chronograph, or illustrate how much air was left in the tank with dive watches. One complication has arguably aged better than all others, becoming even more compelling today than when it first appeared longer ago than you might expect: the humble GMT. And so let’s delve into the fascinating history of the GMT watch.

Tissot Pocket Watch Dual Time 1853

Tissot Pocket Watch Dual Time (1853)

GMTs or dual time watches have been in production in pocket watch form since the 19th century when they started showing inklings of globalisation. As people became able to communicate with far-flung shores, it became necessary to know the time on those very same shores. The earliest and simplest way of doing this was to put two movements into one watch that could be set to different times. They were lovely, produced by brands like Tissot, but not long for this world. It’s a method of timekeeping that has cropped up a few times in history since, like in the Nappey Twin Time from the 1960s. It wasn’t particularly popular though.

Nappey Twin Time 1960s

An advert from the 1960s of the Nappey Twin Time which used two movements to display two different time zones

Dual timezone watches really took off – pun intended – with military flight and specifically, the Longines Zulu Time (recently revived in a modern collection). The name comes from the ‘zero hours’ of Greenwich Mean Time, replaced by the NATO phonetic, so it’s not a surprise that it was a military piece, with a central second time zone hand like we commonly see today. It was rectangular, interesting and is today exceedingly rare, if there even is one outside of Longines archives. It does however show that the first GMT wasn’t what you likely thought it was.

As for who made GMTs popular however… and who first used the term GMT at all, it was of course Rolex. Earning the brand with the crown an important position in the history of the GMT wristwatch. When Rolex debuted the complication in 1954, transatlantic flight was nothing new – two Brits called Alcock and Brown claimed that prize in 1919 after flying for 16 hours with no radio or heaters in the open cockpit of a modified World War I Vickers Vimy bomber from Newfoundland to County Galway – but the arrival of the world’s first jet-powered commercial airliner in 1952, the de Havilland Comet, ushered in the Jet Age, changing travel forever.

Longines Spirit 1925

The first Longines dual time watch (1925)

Jet-powered airliners with new-fangled pressurised cabins were not only 50% faster on average than their propeller-driven counterparts, but they offered greater range and a higher ceiling, allowing them to fly above bad weather. The combination made for a more pleasurable experience allowing passengers to fly faster and further than ever before, while the boom years of post-war America saw demand for international tourism soar. The increasing ease of international travel also brought with it a new biological phenomenon, jet lag, where the body struggles to adapt to sudden changes in timezones, something not lost on the ‘World’s Most Experienced Airline’, Pan American World Airways.

From modest beginnings in the 1920s when two retired US Army Air Corps Majors flew airmail and passengers between Key West and Havana, Pan Am developed global aspirations, cannily buying American Airlines’ international routes in 1950 ahead of the advent of passenger jets. The airline again shrewdly resisted buying the Comet, which suffered a number of catastrophic crashes before being re-designed, instead waiting until 1955 to order 20 Boeing 707s.

Pan Am Rolex Advert
Rolex GMT-master 1955

Rolex Pan Am advert from the 1950s / The first Rolex GMT-Master (1955)

According to James Dowling and Jeffrey Hess in their Rolex bible (an excellent souce for all things Rolex, not just the history of the GMT), The Best of Time, Pan Am was concerned enough about the potential effect on its flight crews to commission a study, which concluded the best protocol was to keep its flight crews on ‘home’ time for the duration of their time away from base. But as access to local time would also be vital, the airline requested a new dual timezone watch from Rolex.

Of course, watches that could display multiple timezones already existed at this point in time; worldtimers had been around since the early 1930s courtesy of Louis Cottier, while Glycine revealed its dual-timezone Airman – which is still in production today – in 1953. The Airman uses a 24-hour main dial with a lockable, rotating bezel with 24-hour scale to track a second time zone and became popular with astronauts on the Gemini and Appollo space programme, and especially with US pilots in Vietnam. But neither the worldtimer nor Airman offered the kind of instant legibility Pan Am was after.

A task force was set-up to answer the problem, led by Pan Am’s Captain Frederick Libby and Rolex’s Rene-Paul Jeanneret, whose official title was Head of Public Relations but, in reality, he was the brand’s “Jack of All Trades” according to Dowling and Hess.

Rolex Ref. 6542 GMT Master

Rolex GMT Master ref. 6542 with aluminium replacement bezel, image credit: Analog:Shift

Libby is often erroneously described as a ‘highly decorated WWII pilot’ and one of Pan Am’s ‘Skygods’ – pilots who flew with Pan Am before WWII – when in fact he was arguably America’s first fighter ace, serving with the British Royal Flying Corps in WWI, before America entered the war and being credited with anywhere between 14 and 24 kills. Libby was invalided out of the military shortly after WWI due to the debilitating illness, spondylitis. It is unclear whether Libby was allowed to fly commercially afterwards, and while there isn’t much in the way of documentation of his post-WWI employment there is a single reference to him as a ‘Pan Am navigator’ which would explain both his ‘Skygod’ status and his presence at Pan Am.

The result of Libby and Jeanneret’s task force was the 38mm GMT-Master ref. 6542 with its distinctive red and blue rotating bezel, which took its inspiration from Rolex’s 1953 Turn-O-Graph (as did its Submariner revealed that same year) making the Turn-O-Graph a strong contender for any ‘most influential watch’ list.

Pussy Galore Goldfinger Rolex GMT-Master

Honor Blackman, as Pussy Galore in the 1964 film ‘Goldfinger’, wearing the first Rolex GMT-Master reference

With a name referencing Greenwich Mean Time, the centre or ‘0’ of international timekeeping since 1884, the watch boasted two elements which allowed it to display two timezones simultaneously; a rotating 24-hour bezel and a fourth hand that completed a single rotation of the dial every 24 hours. The wearer’s current timezone could be displayed by the standard hour and minute hands while ‘home’ time could be tracked by rotating the 24-hour bezel until the arrow-tipped GMT hand pointed at the desired hour.

In a masterstroke of legible design, representing a genuine high watermark in watchmaking, the GMT-Master’s two-tone bezel depicts day and night in red and blue respectively – the fabled Pepsi bezel – allowing the wearer to instantly determine whether it was a suitable time to phone home, or still the middle of the night back at home. In 1964, this first reference would be worn on screen by Honor Blackman’s Pussy Galore in the Bond film, Goldfinger – definitely a landmark moment in the history of GMT wristwatches.

Rolex GMT-Master Captain Warren Reference 6542 Bakelite Bezel

Rolex GMT-Master ‘Captain Warren’ ref. 6542 with Bakelite bezel, image credit: Sotheby’s

Today those earliest bezels are rarer than hen’s teeth. Not only were they made from Bakelite, a plastic more commonly used for substantial objects such as light switches and telephones which cracked easily when used to make such a slim component, but mainly because the luminous material used to in-fill the engraved 24-hour scale was radium and highly radioactive.

Rolex was forced to issue a recall on the ref. 6542 models in stainless steel and 18ct gold (with a brown Bakelite bezel insert) in 1959 at the request of the Atomic Energy Commission, with an offer to inspect said watches. This amounted to 605 pieces across the United States alone that required their radioactive bezels to be swapped with aluminium replacements.

Many of those pieces would have been Pan Am watches, as initially the Captain, First Officer and Navigator of each of its new Boeing 707 aircraft were issued one of the new Rolex GMT-Master ref. 6542 watches which, as the fleet rapidly expanded would have amounted to hundreds of the then $240 USD watches.

Rolex GMT Master Ref 1675

Rolex GMT Master ref. 1675

Pan Am’s own executives became increasingly jealous of the shiny new Rolex’s being shipped to its Chrysler Building HQ before being issued to flight crew, leading to a number finding their way on to the wrists of said executives instead. When Pan Am boss Juan Trippe started noticing these watches around the office he demanded their immediate return so they could be issued as intended but, as a concession, Trippe ordered a batch of around 100 ref. 6542 watches for his company executives with white dials, instead of the standard issue gloss black.

It is believed that Rolex used the final ref. 6542 cases it held in stock for these watches before switching over to the revised ref. 1675 model in 1959, a design which survived in the Rolex catalogue until 1980. An incredibly vital period in the history of the GMT wristwatch.

Rolex GMT Master II Pan Am Advert
Rolex GMT Master II

Rolex GMT-Master II advert from the 2000s / Rolex GMT-Master II (2023)

The GMT hand of the GMT-Master was fixed in relation to the traditional 12-hour hands, meaning both displayed the same time. It was only through rotation of the bezel that the displayed home time could be changed. When the GMT-Master II was introduced in 1983 one of the biggest changes was the decoupling of the 12 and 24-hour hands, allowing both to be independently adjusted. Without doubt one of the most influential developments in the history of the GMT watch.

Despite Pan Am’s prodigious spending habits, the issuing of watches eventually became more exclusive until, at one point, it has been suggested they were instead offered to flight crew at a subsidised price. But by this time the GMT-Master had proved its usefulness to a wider audience and no longer relied on airline pilots for sales, having convinced the new ‘jet-set’ of its advantages.

Baltic Aquascaphe GMT

Baltic Aquascaphe GMT

The GMT complication even proved useful to those who didn’t travel regularly, anyone with a satellite office or family member in a different timezone could benefit from instantly knowing what time it was somewhere important to them. The comparative mechanical simplicity of the GMT complication – separate gearing for the 24-hour hand – also means it is still found in watches at every price point, including quartz and entry-level mechanical pieces like this year’s Baltic Aquascaphe GMT.

The two-tone bezel also proved an aesthetic masterstroke as well as a practical consideration, capable of adopting all manner of colour palettes and the subsequent nicknames that came with them – the Batmans, Cokes, Root Beers – giving GMT watches about as much personality as a wristwatch can be expected to have.

Patek Philippe Complications Calatrava Pilot Travel Time

Patek Philippe Complications Calatrava Pilot Travel Time

The GMT proved adaptable too, when taken to new extremes by brands known for more complicated solutions. Patek Philippe’s Travel Time dropped the rotating bezel entirely in favour of pushers to adjust a 12-hour second timezone hand coupled with an AM/PM indicator. The complication can currently be found in the Swiss brand’s Calatrava and Aquanaut collections. While Gruebel Forsey’s own take on the complication, as found in its GMT Sport watch, is anything but simple, backing up a second timezone with a rotating, three-dimensional globe representing the time in 24 timezones.

While Greenwich Mean Time might have been superseded by atomic timekeeping in the 1960s and eventually dropped altogether by civil aviation in 1972 in favour of Coordinated Universal Time (UTC), those looking for a watch to keep track of two timezones today still seek out the GMT name and its 12 and 24-hour format, for the indelible part it played in the golden age of travel. And let’s be honest, the history of the GMT watch is still being told.

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About the author

James Buttery

James Buttery lives and breathes watches, editing watch industry bible WatchPro before moving to QP magazine. He has been called on to comment on watches and the industry by the BBC, CNN and the International New York Times among others. Now, he’s the head of watches over at Hype Beast.