# Nautical mile and KNOT

## Nautical mile and KNOT

A

The international standard definition is: 1 nautical mile = 1852 metres exactly.

There is no official international standard symbol for the unit nautical mile. The symbols

1 nautical mile converts to:

[*] 6076.1155 feet

[*]1.852 km (exact)

The nautical mile was historically defined as a minute of arc along a great circle of the

International agreement was achieved in 1929, when the International Extraordinary Hydrographic Conference, Monaco adopted a definition of 1 international nautical mile = 1,852 metres, very close to the average length of one minute of latitude i.e. one minute of arc along a line of longitude (a meridian).

The derived unit of speed is the KNOT, defined as one nautical mile per hour.

The term "knot" derived from the practice of using a knotted rope as a method of gauging speed of a ship. The rope would be thrown into the water and the rope trailed behind the ship. The number of knots that passed off the ship and into the water in a given time would determine the speed in "knots".

**nautical mile**is a unit of length. It is not an SI unit. The nautical mile is used around the world for**aviation**purposes.**Definition**The international standard definition is: 1 nautical mile = 1852 metres exactly.

**Unit symbol**There is no official international standard symbol for the unit nautical mile. The symbols

**NM**,**nm**and**nmi**are commonly used in some areas.**Conversions to other units**1 nautical mile converts to:

[*] 6076.1155 feet

[*]1.852 km (exact)

**History**The nautical mile was historically defined as a minute of arc along a great circle of the

*Earth*. It can therefore be used for approximate measures on a*meridian*as change of*latitude*on a*nautical chart*. However, like all planets, the Earth is not a perfect sphere. It bulges at the*equator*like a spinning top, so the length of one minute of arc on the Earth's surface varies from 1862 m at the poles to 1843 m at the Equator. The Earth's surface also has bumps and hollows like a potato. Thus, there is no fixed relationship between angle and arc length along the Earth's surface; one minute of arc can vary in length by tens of metres.International agreement was achieved in 1929, when the International Extraordinary Hydrographic Conference, Monaco adopted a definition of 1 international nautical mile = 1,852 metres, very close to the average length of one minute of latitude i.e. one minute of arc along a line of longitude (a meridian).

**Associated units**The derived unit of speed is the KNOT, defined as one nautical mile per hour.

The term "knot" derived from the practice of using a knotted rope as a method of gauging speed of a ship. The rope would be thrown into the water and the rope trailed behind the ship. The number of knots that passed off the ship and into the water in a given time would determine the speed in "knots".

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Registration date : 28/10/2007

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