why does GMT only rotate once in 24hrs

[shaggy]

im wondering why rolex made the extra hour hand only rotate the dial once in 24 hrs hours as opposed to twice like the normal hour hand?
was it a cost issue or a technical issue?
and is it technicaly harder to have it rotate twice in 24 hrs?

[Dan Pierce]

Originally Posted by shaggy

im wondering why rolex made the extra hour hand only rotate the dial once in 24 hrs hours as opposed to twice like the normal hour hand?
was it a cost issue or a technical issue?
and is it technicaly harder to have it rotate twice in 24 hrs?

So the wearer can determine day or night [1:00 am vs 1:00 pm] on a second timezone.
dP

[Poohsan]

To tell time in 24 hour increments not 12 increments.

“A 24-hour watch is a type of watch with an hour hand that completes a revolution every 24 hours. This type of watch is especially useful for airplane pilots, astronauts, members of the military, or anyone who uses a 24-hour clock.” – from: http://en.wikipedia.org/wiki/GMT_Watch

[shaggy]

Originally Posted by Dan Pierce

So the wearer can determine day or night [1:00 am vs 1:00 pm] on a second timezone.
dP

is that all
i need to get out more
there was i thinking that it would include more engineering (hence why this post is in watchtech)

[Dan Pierce]

Aaron is correct as worldwide time navigation is based on 24 hour military time. But I need to know if they're out of bed before I call Guam.
dP

[Tools]

Everybody is just guessing... none of us actually know the answer..

However, the original GMT had hands that were synced together (the improved GMT II is fairly new), so by your reasoning, both hands would be in the same place.........

That would have been nothing more than a regular watch with a rotating bezel......... it would be the Turn-O-Graph, which already existed..


(Both the original GMT, and the Sub were developed from the Turn-O-Graph base)

[shaggy]

i can understand the concept of 24 hr time and appreciate that the bezel helps out with the telling of day/night with the dark colour blue is from 18 - 6 ie dark and the lighter red being from 6 - 18 ie daylight in the second timezone?
of course an all black bezel wouldn't help with this so we are back to the 24hr part of the bezel

[Balboa]

The original GMT was intended to help pilots keep track of GMT (now UTC). UTC is kept on a 24 hour scale. If the extra hand moved on a 12 hour basis, it would be useless for its intended purpose.

Of course newer versions of the watch allow some additional flexibility in the use of the fourth hand, but the original purpose is still valid.

Mark

[JJ Irani]

Originally Posted by shaggy

im wondering why rolex made the extra hour hand only rotate the dial once in 24 hrs hours as opposed to twice like the normal hour hand?
was it a cost issue or a technical issue?
and is it technicaly harder to have it rotate twice in 24 hrs?

Even if Rolex could rearrange the gearing for the 24-hour hand to rotate TWICE in 24 hours, it would defeat the very purpose for which the watch was intended!!

[Tools]

Originally Posted by Balboa

The original GMT was intended to help pilots keep track of GMT (now UTC). UTC is kept on a 24 hour scale. If the extra hand moved on a 12 hour basis, it would be useless for its intended purpose.

Of course newer versions of the watch allow some additional flexibility in the use of the fourth hand, but the original purpose is still valid.

Mark

No, no, no.......The original GMT was intended for pilots to keep track of their HOME time... (GMT is just the name of the watch....not the hand or it's intention)

The watch was set to HOME time.... both hands, since they were synced. The bezel was rotated to each new time-zone to keep track of where you are in the world, but the pilot kept a home reference to sleep by and manage jet lag... That was the whole point for Pan Am's request to Rolex for development of the watch..

[petespendthrift]

Whatever the intended method of use for the original GMT, the GMT-II and Exp-II are far more useful to pilots because the 24 hour hand can be left on GMT/UTC. As a commercial pilot I am a lot more interested in what GMT/UTC is than home time as all flight plans, weather etc. use UTC. When I need to ring Mrs. Spendthrift - temporarily requiring home time - I use the hours offset from GMT (eg. UTC +6 hours) - which can be worked out in my head or on the bezel. UTC offset simplifies time zone calculations which is why its what almanacs use.

The fact that Rolex called the original model the GMT does give some indication that they intended pilots to be able to use it to work out GMT.

A second 12 hour hand would not be able to achieve any of these functions so would be useless.

[ParisDakarBmw]

I think it's an excuse to have a cool red hand.................JK

The second time zone in 24 hour sounds better. If your on the other side of the pond, you would be able to tell the true time with no math involved.

[goldminer]

Originally Posted by Tools

No, no, no.......The original GMT was intended for pilots to keep track of their HOME time... (GMT is just the name of the watch....not the hand or it's intention)

The watch was set to HOME time.... both hands, since they were synced. The bezel was rotated to each new time-zone to keep track of where you are in the world, but the pilot kept a home reference to sleep by and manage jet lag... That was the whole point for Pan Am's request to Rolex for development of the watch..

Not quite .... Pan Am requested a watch that could simultaneously record two time zones.

Commercial flights use UTC (previously used GMT) or "Zulu" time. Weather forecasts, flight plans and air traffic control clearances all use UTC to avoid confusion about time zones. They do not use local times, so if a pilot was using the watch as it was originally intended he wouldn't have it set on HOME time but on GMT. The suggestion that it was used to manage jet-lag seems rather fanciful to me.

[2005rivers]

I heard it was for nano seconds












Realy joking, I agree with above posts

[larrysb]

I'm a pilot (non-commercial though I hold instrument and single and multiengine licenses), and I use my GMT watch with the 24 hour hand set to UTC time. (the currently correct name for the meridian timezone, which is kept in 24-hour time and not subject to DST, but is subject to leap seconds to keep it in sync with UC-1 time, derived from astronomical and solar observations from the earth's perspective, as opposed to absolute time scales such as the GPS Epoch).

(Sorry for the smeared sentences. I had to write a research paper for my company once on all the different time bases).

[mopsey]

This is one of those jokes threads, ain't it?

[Tools]

Originally Posted by mopsey

This is one of those jokes threads, ain't it?

It must be........ Some of these posters are just guessing and haven't done much actual study or research of the watch and why it was developed....

[MikeyTX]

It is rather evident that many haven't bothered to read any of your in depth threads.

[Flyjet601]

Well I have always looked at the 4th hand as my GMT time. Really I could care less about what time it is at home.

If I travel to a different time zone, I have to adapt as quickly as I can to function in this new time. Knowing I am 8 hrs ahead or behind of home is irrelevant in adapting to jet lag, if I really need to know what time it is at home I rotate the bezel accordingly. There is no easy way to adapt to jet lag and certainly knowing what time it is at home is no help(at least not to me and everyone I know who travels a lot).

As stated above, all time in aviation are in UTC, so a quick look a your wrist and you know what time(UTC) it is wherever you are in the world. This idea of knowing home time as stated I believe in the original Rolex ad I think is another marketing idea to sell the watch to the general public. Although as many people use, there are other uses for the 4th hand.

[MikeyTX]

Originally Posted by shaggy

im wondering why rolex made the extra hour hand only rotate the dial once in 24 hrs hours as opposed to twice like the normal hour hand?
was it a cost issue or a technical issue?
and is it technicaly harder to have it rotate twice in 24 hrs?

Same reason a chicken crosses the road .................

[David Woo]

I was gonna say "the same reason the sun only comes up once a day" but they say I'm way too cynical.
DW