## Friday, 20 July 2018

### Measurement conversions

Standardized conversions
1 Nautical mile = 6076 feet        1852.00 Meters
1 Nautical mile = 10 Cables        1852.00 Meters

Measurement conversions
1 fathom = 6 feet                  1.8288 Meters
1 chain    = 66 feet            20.1168 Meters
11 fathom = 1 chain              20.1168 Meters

1 Metre = 39.37008 inches
1 Metre = 3.280840 feet
1 Metre = 1.093613 yards

1 inch (1") = 2.54cm
1 foot (1') = 30.48cm

Rough metric equivalents
3 millimetre    = 1/8 of an inch
6 millimetre     = ¼
8 millimetre     = 5/16
10 millimetre     = 3/8
12 millimetre     = ½
14 millimetre     = 9/16
16 millimetre     = 5/8
19 millimetre     = 3/4
25 millimetre     = 1

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A nautical mile is a System of Units (SI) derived unit of measurement defined as exactly 1852 meters (about 6,076.1 feet). A nautical mile is based on the circumference of the earth and traditionally, it was defined as the distance of one minute of latitude on the earth’s surface. One minute of latitude is equivalent to one sixtieth of a degree of latitude. Today it is an International System of Units (SI) derived unit, being rounded to an even number of meters and remains in use for air and marine navigation. The standardised or SI unit is also used as the measurement in the definition of territorial waters.

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

In the past there was the Imperial nautical mile, often referred to as the Admiralty mile, or an Admiralty measured mile. This unit was defined by its relation to the Admiralty Knot, 6,080 imperial feet per hour, so 1 imperial nautical mile is about 1,853.181 meters. The measurement was abandoned in 1970 and due to legal reasons references to the obsolete unit are converted to 1,853 meters.

The geographical mile is a unit of length determined by 1 minute of arc along the Earth's equator. The length of the Equator in the World Geodetic System WGS-84 (usual GPS datum) is 40075016.6856 m which makes the geographical mile 1855.3248 m. In any standard, the length of a degree of longitude at the equator (at the Equator) is thus exactly 60 geographical miles.

Source of information of the nautical mile as a unit of measurement is various but include information obtained from, Wikipedia, American Coast Guard, NOAA.