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Thread: How fast is 1 knot?

  1. #1
    Paul Foster
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    Default How fast is 1 knot?

    My son asked me today how fast is 1 knot (in MPH) and I had no idea how fast
    it was!

    Can you help?

    TIA

    Paul


  2. #2
    Pete Styles
    Guest Pete Styles's Avatar

    Default How fast is 1 knot?

    1 knot is one nautical mile per hour.
    If you are wondering why we bother with the nautical mile, its because its 1
    minute of latitude (ie 1/60 of a degree) and therefore very useful to, for
    example, sailors, because it can be directly measured from the latitude scale on
    a chart. Thus it has a direct relationship to the size of the earth. The usual
    rule of thumb is that it's one and a seventh of a statute mile per hour.
    HTH,
    P.

    Paul Foster wrote:

    > My son asked me today how fast is 1 knot (in MPH) and I had no idea how fast
    > it was!
    >
    > Can you help?
    >
    > TIA
    >
    > Paul

  3. #3
    Pete Styles
    Guest Pete Styles's Avatar

    Default How fast is 1 knot?

    >
    > You are quite right Peter, a nautical mile is approx 800 feet longer than a
    > statute mile, my apologies.
    >
    > My Garmin, when used in the car, disagrees with my speedo as the Garmin is
    > set to nautical miles, but the new tyres I have just fitted mean that the
    > rev. counter no longer reads as fast for a given speed than before the tyres
    > were fitted.
    >
    > If I therefore set my Garmin to read statute miles, or even kilometers, am I
    > likely to win more races if I buy new sails for the yacht?
    >
    > Dennis


    <g>
    Sadly, talent and money seem to be the only recipe for success, and I can't lay
    claim to enough of either!

  4. #4
    Alan Frame
    Guest Alan Frame's Avatar

    Default How fast is 1 knot?

    Peter Verdon <news@verdonet.organisation.unitedkingdom> wrote:

    > (That is, 1 knot is 1.15mph; 1mph is 0.87kt.)


    Things can get 'interesting' when one forgets to switch a GPS from knots
    to statute when moving it from a boat to a car....

    rgds, Alan

  5. #5
    Jeff Richards
    Guest Jeff Richards's Avatar

    Default How fast is 1 knot?

    Sigh. Please replace every reference to longitude in the above post with
    latitude, and remove the last comment.
    --

    "Jeff Richards" <JRichards@********.au> wrote in message
    news:VkpEc.70914$sj4.27790@news-server.bigpond.net.au...
    > According to Peter Heaton 6080 was decided because it is the length of a
    > minute of longitude at latitude 48 degrees. He suggests that this is an
    > 'average', but I rather think it was convenient for British sailors.
    >
    > My calculation for latitude 48 gives 1853.17 metres or 6079.16 feet, which
    > I guess is within the error of the calculation. It's
    >
    > 111132.92 + (-559.82 * Cos(2 * L)) + (1.175 * Cos(4 * L)) + (-0.0023 *
    > Cos(6 * L))
    >
    > where L is the latitude. Working backwards, this means that the new unit
    > of 1852m is exactly one minute of longitude at latitude 44.4.
    >
    > Note that your 60.3 NM is at 90 degrees latitude, where a minute of
    > longitude has become a little irrelevant!
    > --

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