Question is - How we manage the change in time
while travelling around the world
Who tells us when to change Ship's time
and How does this change in time zones affect us
Assalamoalikum and welcome back to "Orange Shots"
In todays's video I will explain
how we manage different time Zones
How and when we change the ship's time
and how we synchronise our watches with the
ports Of arrival.
First of all there are at least 5 times of interest to us,
that we need to know about
They are called GMT or Greenwich Mean Time,
ZT or Zone Time,
LT or Local Time,
SMT or Ship's mean Time, and ST or Standard time.
Another fun fact is that time is independent of latitude,
it doesn't really matter How North or South of Equator you are,
the time is dependent upon longitude.
Our Earth is divided into 360 divisions just as a Circle would,
Only difference is That this 360 degrees of division
is further divided into 180 degrees East and 180 degrees west,
We call them the East Longitudes and the West Longitudes
The reference point here is Greenwich observatory in UK,
The Longitude passing Through the greenwich observatory
is referenced as "0" degrees longitude This meridian line is also called "Prime Meridian",
the Longitudes East of this observatory are referenced as
Eastern longitude and the longitudes west of
This Meridian are Called - You guessed it right - West Longitudes.
And the time that is kept here, at Greenwich observatory, is known as GMT
or Greenwich mean Time.
Our clocks in the whole world are based on this division of longitudes,
There are 360 divisions of the world and 24 hours in a day,
and if we divide 360 degrees by 24 hours then then answer would be 15 -- that means
that for Every 15 degrees of change in Longitude,
the clocks would change by One hour.
For making this division easy, from 7.5 degrees west of Greenwich to 7.5
degrees East of Greenwich is Time Zone 0 .. GMT,
For every 15 degrees of change in longitude Thereafter,
1 hour is added or subtracted, this One hour Zone is Called Time zone.
To find out your time Zone, you need to know your longitude,
For example let's Take longitude of Islamabad, Islamabad is located at 33.68 N, 073.04 Degrees
East, add 7.5 degrees to it (to compensate for GMT)
the answer is 80.5 degrees Now we already know that every 15 degrees
of longitude makes One hour,So now divide 80.5 degrees
by 15 degrees and your answer will be 5.36 --
Ignore anything that's in points and our answer will be 5.
That is how we know that Islamabad's Time zone would be
GMT + 5 This is called ZT or zone Time.
Now, To understand LT or Local time, Simply take your longitude and divide it By
15, the answer will be your Local time,
for example, let's consider Islamabad Again, if we divide Islamabad's longitude - 073.04
- by 15 then the answer Will be 4.86 hours or 4 hours
52 minutes, this is called as LT or Local time
If you add Greenwich time to it, that is if you add 7.5 degrees to this longitude
Then your answer would be 80.54 degrees or 5.369 Hours
or 5 hours 22 minutes Now this time would be called LMT or Local
mean time.
Now let's understand, Standard Time, this is different from GMT and LT or LMT
For this Example let's consider India, From our early examples, if we consider
Different cities of India, You can see that they lie in different time
Zones Some are in Zone Time 5, some in 6 and A few
in 7.
But as we all know India Doesn't keep different time Zones
for different states or parts of the country They keep one time zone across all of India
that is GMT+5.5 or -5.5 however You may prefer, This is called as Standard time,
despite the country extending To different time zones,
the government prefers to keep one standard time,
This standard time may be corresponding to the Zone Time
in which this country Lies or it may not be.
Another Example is Pakistan and Afghanistan, although Most part of Pakistan and All of
Afghanistan lie in the same Zone time, Afghanistan keeps
-4.5 as their standard time and Pakistan keeps
-5 as their Standard time.
So contradictory to both the above (GMT and LT)
the Standard time is at sole
Decision of the government, but it's not that far away for the Zone time
where That country lies on the map of the earth.
If they drift too far off from The zone time then all the sunrise and sunset
timings will be too much off ...
Another interesting thing here is the Daylight Saving time or DST that many
Countries use.
In the Northern spring Season the clocks are advanced by 1 hour
And in the Northern Autumn season the clocks are retarded by one hour,
This is done to take advantage of sun rising early in Summer season,
This gives one hour of extra light in the day
and helps in reducing electricity Consumption during Summers.
But not every country does that and the exact dates
On which the clocks are advanced or retarded depend from country to country and
Usually Sundays or Saturdays are chosen to do so
in order to have minimal impact On the routine of people.
Now let us talk about Us, the Ships, What are the timings important
for Us and How do we manage all of these time changes.
For Us, 2 of the times are most important, 1st is UTC or the Universal Time co-ordinated
and 2nd is Standard time of the countries.
Now you guys must be wondering What is this UTC
and some might be even saying That Oh, it's the same as GMT Captain,
why would you mention it separately?
No dears, that is not True, for most part the GMT and UTC are quite similar
But the main building block of UTC and GMT are different, GMT only considers Change of
1 hour every 15 degrees rotation of Earth,
the UTC takes into Account the actual rotation of earth around its axis,
and while GMT considers 365 days as a year, UTC adds one leap second every 19 months to
keep all Of the world co-ordinated
and all clocks in the world are actually based on UTC,
although the difference is small but important and that is the reason We actually consider
only UTC when synchronising our clocks.
The Standard time is important to us because obviously we would maintain the
Time of the country where we are arriving, just a day or couple of days before
The Arrival there.
But the most interesting things actually happen when we are at sea,
As then we keep a time that is called SMT or Ship's mean time.
In the beginning of video I told you guys that when we go east of Greenwich
Meridian the time is added for every degree of longitude
that we move EAST And Subtracted for every degree of longitude
we move West.
Now a ship is Always or Mostly in motion at sea,
and it would be very silly if we keep changing Our clocks every degree or minute or second
change longitude...
So naturally that's not how we Do it.
I personally keep in view the daylight times, when the sun will rise And Set each day
so that we have complete daylight available for everyone to work
And then we keep a check on which time Zone we are in,
we usually just see our Longitude and calculate it.
And the clocks are actually retarded or advanced by One hour
unless we are going To a country that has half of hour added to or subtracted from Time
Zone.
This advance or retard of clocks is performed at midnight so that every watch keeper
Easily knows when he needs to adjust his timings.
And naturally people are happy when the clocks are retarded
- that means one hour Extra to sleep vs when the clocks are advanced
which means One hour less to sleep.
And unlike you people on land we don't have the luxury of
advancing and retarding The clocks only on holidays,
these changes are happening pretty much any day required.
For a new comer on vessel this might be a little too much
to adjust to, but We, the seasoned mariners are well used to
this change in clocks.
And while we do Feel happy or sad when the clocks
are retarded or advanced - there's actually Nothing we can do about it
except for embracing the Change.
The Biggest shock or exciting thing - depending upon the people -
is when we cross The DATE LINE which is close to and usually synonymous to
anti - meridian - or 180 degrees of longitude as at that time the The vessel crosses DATE
LINE - which means that either One day completely
disappears From your life or One day is added again
and you get to re-live the same day.
Usually when the ship crosses the Date line going eastward One day is reversed --
Just for fun we make an announcement on the ship telling everyone that now
they Have gone one day in the Past ... Most people at this point are happy.
But when the ship crosses the dateline going westward
- one day is gained and is Wiped off from one's life ...
People are usually excited at the fact that they
Didn't have to work for a day (in theory only) ...
Now this process of advancing and retarding clocks
is performed very swiftly across The ship with just a few touches,
all the watch keeper needs to do is punch in How many minutes or seconds
or even hours he wishes to adjust and once this command is executed here,
all ship's clocks start advancing or retarding in harmony.
So that was pretty much it for today's Video, If you guys found this video useful
Or learned something from it, then don't forget to give
video a like, Share it with your friends
and Consider subscribing to my Channel.
With tonnes of love for my Orange Shots Family and To-be Orange Shots family
This is me Zahid Nisar, you guys are watching Orange Shots
Until the next Video "Allah Hafiz"