Knots are for boats!
Join Date: Jun 2004
Location: Australia
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It's a de-facto Metric Unit
I'm surprised that someone hasn't raised the point that the Nautical Mile is ESSENTIALLY a Metric unit, being defined as EXACTLY 1852 M, and equal to 1 minute of arc of latitude. Degrees, Minutes, and Seconds are an integral part of the Metric system. I say essentially a Metric unit, see the extract from Wikipedia below, where, in red, it is noted that it is accepted for use in the International System of Units by the BIPM. It's equivalent in feet or other units is a surd.
Courtesy of Wikipedia - The nautical mile (symbol M, NM or nmi) is a unit of length that is about one minute of arc of latitude measured along any meridian, or about one minute of arc of longitude at the equator. By international agreement it is exactly 1,852 metres (approximately 6,076 feet).
It is a non-SI unit (although accepted for use in the International System of Units by the BIPM) used especially by navigators in the shipping and aviation industries, and also in polar exploration. It developed from the sea mile and the related geographical mile.
The nautical mile remains in use by sea and air navigators worldwide because of its convenience when working with charts.
- END Wikipedia quote.
The International Nautical Mile was established in 1929, adopted by the U.S.A. in 1954, and belatedly by the Brits in 1970 when they finally standardised and dropped their beloved 6080 ft Nautical mile (But it's legacy lives on in things like the constant of 38.94 instead of 38.9679 for Mach Number to TAS computation ~ some errors never die!).
A system that essentially provides for navigation, and as a bonus is an accepted de-facto member of the Metric system, is, I believe, more useful and appropriate than the distance that a Roman soldier could march in full kit between rests
Time to bury the milus and the mile with the cubit and other quaint measures.
Best Regards,
Old Smokey
Courtesy of Wikipedia - The nautical mile (symbol M, NM or nmi) is a unit of length that is about one minute of arc of latitude measured along any meridian, or about one minute of arc of longitude at the equator. By international agreement it is exactly 1,852 metres (approximately 6,076 feet).
It is a non-SI unit (although accepted for use in the International System of Units by the BIPM) used especially by navigators in the shipping and aviation industries, and also in polar exploration. It developed from the sea mile and the related geographical mile.
The nautical mile remains in use by sea and air navigators worldwide because of its convenience when working with charts.
- END Wikipedia quote.
The International Nautical Mile was established in 1929, adopted by the U.S.A. in 1954, and belatedly by the Brits in 1970 when they finally standardised and dropped their beloved 6080 ft Nautical mile (But it's legacy lives on in things like the constant of 38.94 instead of 38.9679 for Mach Number to TAS computation ~ some errors never die!).
A system that essentially provides for navigation, and as a bonus is an accepted de-facto member of the Metric system, is, I believe, more useful and appropriate than the distance that a Roman soldier could march in full kit between rests
Time to bury the milus and the mile with the cubit and other quaint measures.
Best Regards,
Old Smokey
