Author Topic: [Chat] Miles, knots and more  (Read 1550 times)

Offline Nord

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[Chat] Miles, knots and more
« on: August 13, 2021, 10:04:46 am »
I also have no idea how much a mile or a knot is... I'm from Europe... that's why I added conversion to kilometers and to km/h.
By the way, nautical miles are not equal to american mile. It is a meridian length of one arc minute size. Useful for those who navigate over the globe. But hard to understand to surface people. :)
Nevertheless I prefer kilometers too.
« Last Edit: February 12, 2023, 11:38:39 am by Meridian »

Online Meridian

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Re: Miles and more
« Reply #1 on: August 13, 2021, 10:22:59 am »
It is a meridian length of one arc minute size.

I will also just add that "meridian" here is not my nickname, but a real word used in geography meaning "line of longitude": https://en.wikipedia.org/wiki/Meridian_(geography)
Just in case somebody started thinking I invented my custom units :P

Offline Leprechaun

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Re: Miles and more
« Reply #2 on: August 13, 2021, 05:12:29 pm »
By the way, nautical miles are not equal to american mile. It is a meridian length of one arc minute size. Useful for those who navigate over the globe. But hard to understand to surface people. :)
Nevertheless I prefer kilometers too.

That's the modern definition, but you can't possibly believe that in the days of sailing ships they had sufficient instrumentation to calculate how many arc-minutes a ship had travelled or was moving at.

A seaman would throw a log over the side, tied to a rope with regularly spaced knots, the earliest version being every 100 feet. (After all, who wants to divide 5280 by 60 and then pace off that amount of rope? The calculation is just as sticky in meters.) The sailor counted how many knots when through his fingers in 1 minute, and that was the ship's speed. X knots per minute = X hundred feet per minute, or X times 6000 feet per hour, or X Knots.

Sometime later (undoubtedly AFTER someone was able to accurately calculate the length of an arc-minute) a knot was standardized at 1852 meters or 6076 feet. Interestingly enough, the US and the UK were among the last countries to accept the international definition, in 1954 and 1970 respectively.

Offline krautbernd

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Re: Miles and more
« Reply #3 on: August 13, 2021, 07:46:42 pm »
That's the modern definition, but you can't possibly believe that in the days of sailing ships they had sufficient instrumentation to calculate how many arc-minutes a ship had travelled or was moving at.
Not only possible, but as they say inevitable.

Quote
A highly skilled and experienced navigator can determine position to an accuracy of about 0.25-nautical-mile (460 m)

Together with the invention of an accurate and reliable marine chronometer - which came about in the 1760s (and I'd argue would still be "in the days of the sailing ships") and solved the longitude problem - I'd argue instrumentation would have been sufficient to calculate travelled distance and speed to a sufficient degree.

Offline Solarius Scorch

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Re: Miles and more
« Reply #4 on: August 17, 2021, 02:49:12 pm »
It's simple, one knot is exactly one mile per hour. :)

And to be honest, knots are commonly used for sea vessels, also in Europe. But miles are not, I think.