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Do you all know about international dateline but what about the nautical dateline? In this article, you will learn about the major difference between the nautical dateline and the international dateline. The International Dateline is a line on the Earth’s surface that marks the start of one day and the end of the next. The 180th meridian is paralleled by a dotted line that runs from pole to pole, which is called the Nautical dateline. Read the article further to find out more about the difference between nautical dateline and international dateline.
International Date Line
What is International time/coordinated universal time?
The major time standard by which the planet governs clocks & time is Coordinated Universal Time UTC, which is a replacement for Greenwich Mean Time.
What is the IDL?
The International Date Line (IDL) is an invisible line on the surface of the Earth that marks the transition from one day to another. It is a globally recognised demarcation on Earth’s surface and serves as the transition between calendar days.
Where is the IDL?
The International Date Line is around 180 degrees east or west. It’s halfway around the globe from Greenwich, UK, where the prime meridian serves as the time zone point of reference.
The dateline:
- Divides the Western and Eastern Hemispheres
- Is a line from the North Pole all the way to the South Pole
- Bends around mainlands and country borders rather than being straight
Along either side of the dateline, there are different days
The International Date Line is exactly the point at which each calendar day begins, and it is also referred to as the “Line of Demarcation.” Why? IDL separates two calendar dates: crossing the dateline east subtracts a day, and crossing it west adds a day.
When was it established?
The international dateline which was created in 1884, runs across the middle of the Pacific & approximately follows a 180-degree north-south line on the globe. From 1884 till the present the date-line has changed many times upon international discussions
What is the use of IDL?
The international date line serves as a “dividing line” that separates two calendar dates. Once you cross the line, you essentially become a time traveller! It’s one day late if you travel to the west; if you travel back, you’ve “travelled back in time.”
Nautical date line
What is Nautical time?
Nautical time was designed so that ships on the high seas could communicate their local time. For every 15 ° variation in a boat’s longitudinal position, nautical time zones are divided into one hour increments.
What is the history of Nautical Time and Date Line?
Nautical timekeeping began in the early twentieth century as a regular way of keeping time at sea, however, it was mostly implemented in military fleets before World War 2. This time-keeping system is exclusively used only for communication systems and to adjust for minor mistakes that may occur while utilising Greenwich Mean Time (GMT) during high-seas navigation. It’s usually exclusively utilised for trans-oceanic voyages because captains don’t usually modify the timekeeping for small distances like channels or interior waters.
The Anglo-French Conference on Time-keeping at Sea suggested the development of nautical standard hours, nautical standard time zones, and the nautical dateline in 1917. The norm should extend to all ships, whether military or civilian, according to the conference’s recommendations. Between 1920 and 1925, the major armies adopted these zones, but many smaller commerce ships did not until World War II.
What is a Nautical Date Line?
On time zone maps, a nautical date line is suggested but not explicitly depicted. It is a pole-to-pole dotted line that parallels the 180th meridian. However, it is disrupted by territorial seas next to land, causing gaps beyond that.
What is the Nautical Time and Date Line used for?
In actuality, nautical timings are solely utilised for radio transmission and other similar purposes. The ship may utilise an appropriate time of its selection aboard the ship, for example, when organising labour and lunch hours.
After the ship enters some other time zone, the captain is entitled to alter his / her clocks at a predetermined time, usually at midnight. This is how ships on long-distance voyages alter the time zone on board. Even if they fly through various time zones, including between the UK or continental Europe, the commander may not reset the clocks for brief crossings.
Onboard signs on passenger ships frequently also include nautical as well as on-time zones. The terrestrial time zone should be used whenever referencing daily schedules and connecting with the land.
Nautical Dateline and International Dateline: Difference
Nautical Date Line | International Date Line | |
Dateline | A nautical dateline is a pole-to-pole dotted line that parallels the 180th meridian | It bends around mainlands and country borders rather than being straight |
Time | Used for nautical time | Used for international time/Greenwich meantime |
Uses | Nautical timings are solely utilised for radio transmission and other similar purposes | The international date line serves as a “dividing line” that separates two calendar dates, for convenience |
Establishment date/ history | Nautical timekeeping began in the early twentieth century as a regular way of keeping time at sea | The international date line was created in 1884 |
Conclusion
To summarise, here’s the difference between nautical dateline and international dateline. The International Date Line (IDL) is a line on the Earth’s crust that indicates the change from one day to the next. There are different times from either side of the dateline! Nautical time was created to allow boats on the open seas to communicate with one another in local time. Nautical time zones are separated as one hour increments for every 15 degrees change in a ship’s longitudinal location. A nautical date line is a dotted line that runs from pole to pole and crosses the 180th meridian.
