Why the waters aren't metric (was: Control of immigration)
Mon, 29 Oct 2001 23:19:38 +0000
Lisa Dusseault writes:
>Imagine a Canadian company unable to sell its high-quality luxury boats in
>US due to trade restrictions. When the restriction is lifted, suddenly the
>Canadian company has
>access to a much larger market. .. Their "American version" (shows knots
>and miles, not kilometers) ..
That gave me a small chuckle. Because there was an attempt,
at one time, to metricize nautical navigation.
People who have never done any navigation are puzzled that
a nautical mile is different from a statute mile. What they
don't realize is that the nautical mile is a natural unit
of length. Divide a meridian into 360 degrees. Divide each
degree into 60 minutes. Each minute is one nautical mile.
What's the circumference of the earth? 360 * 60 = 21,600
nautical miles. Every degree of latitude is one nautical
mile. If you can sight the north star, you know how many
nautical miles you are from the equator. Every degree of
longitude is approximately one nautical mile near the
equator. Away from the equator, longitudinal meridians grow
closer by the cosine of the latitude, until they meet at
The meter also was meant to be a natural unit of measure. It
originally was defined so that the circumference of the earth
was 40,000 kilometers. At one point, some crazy French folks
thought that this would be the wave of future navigation. You
can find old compasses that divide the circle into 400 degrees.
Forty points to the compass?! Come now, everyone knows it
should have 32, a power of two. Satisfying neither the French
metricizers nor the traditional compass makers, we stick with
the old Sumerian standard. People like 360 degrees in a circle,
and 24 hours in a day. (Quick! How many degrees in an hour?)
The push for a metricized day and circle went nowhere. Pure
math is done in radians, and everything else is convention.
Nautical miles and knots are the navigational standard. From
Canada to Tasmania.
At least the rest of the metric system makes sense. Right?
Here is a master rigger's contrary opinion:
Don't blame me. I think anyone who tries to splice wire needs
their head examined.
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