Loved hearing an ISS astronaut (mission commander) correct a senator over flying vs. falling (in orbit).

quote:

Originally posted by YellowJacket:

quote:

Originally posted by MikeinNC:
2000 yards to be exact....

1852 meters, 6076 feet, 2025 yards.

Ha I was being facetious! Forgot my smilie!

quote:

Originally posted by Patriot:
We even have Zulu time (GMT)...all subs no matter where in the world share the same, exact time.

BOOGITY!!!!!

I wish surface did that. Standing watches was a russian roulette of whether you got screwed. Cross a time zone going west, your watch got stretched by an hour until you were relieved. And it wasn't a given that you would get your watch shorter by an hour going East.

"A nautical mile is based on the circumference of the earth, and is equal to one minute of latitude. It is slightly more than a statute (land measured) mile (1 nautical mile = 1.1508 statute miles )."

Is the 1.1508 statute miles derived from 1 minute of latitude at the equator? Or does it matter?

quote:

Originally posted by MikeinNC:
2000 yards to be exact....

Close, but no cigar. A nautical mile is slightly more than 2025 yards.

I've known the relationship between the circumference of the Earth and the nautical mile for decades. However, the "minute of arc" differs whether measured on a circle of longitude or at the Equator (the Earth is not a perfect sphere--it's squashed and the Equator is slightly longer than a circle of longitude).

FWIW, the meter is also related to the circumference of the Earth. It was originally specified as "one ten-millionth of the shortest distance from the North Pole to the equator passing through Paris". In later years a standard metal bar was built to be the formal designation (stored in Paris). In 1960 it was specified as "a specific number of wavelengths of light from a specific transition in krypton-86". The most recent definition of the meter is based on the speed of light in a vacuum, or 299792458 m/sec, where the second is in turn specified in terms of a Cesium frequency.

FWIW, our English "inch" has also had many definitions. In ancient times it was the "length of 3 barley corns taken from the center of the cob, laid end to end"; later defined as 1/12 of a Roman "foot" (the Latin term uncia "twelfth" is the basis for "inch"). Since the 1960s the inch has been defined as exactly 25.4 millimeters. This value only differs from the former official definition by a figure in the sixth significant figure, so the errors in practical former measurments are inconsequential.

flashguy

Measure it with a micrometer, cut it with an axe.

quote:

Originally posted by nhtagmember:
and lets not get started on twilight

there are only three of those...

but here is my big mystery...

if Nautical is spelled with an N, why is knots spelled with a k

Nautical because "nautilus" and knots because those were tied into the line which drug along side the ship to determine speed.

NOW, if you spend quality time taking care the brightwork, you won't get the dogwatch.

Pretty hard to fathom how deep this yarn will go.

quote:

Originally posted by LS1 GTO:

quote:

Originally posted by nhtagmember:
and lets not get started on twilight

there are only three of those...

but here is my big mystery...

if Nautical is spelled with an N, why is knots spelled with a k

Nautical because "nautilus" and knots because those were tied into the line which drug along side the ship to determine speed.

NOW, if you spend quality time taking care the brightwork, you won't get the dogwatch.

Pretty hard to fathom how deep this yarn will go.

...and Don't forget to keep an eye out for sea bats while on the mail buoy watch.....and if you misplace your padeye wrench you might need a Boatswain punch

quote:

Originally posted by Patriot:
We even have Zulu time (GMT)...all subs no matter where in the world share the same, exact time.

BOOGITY!!!!!

Yeah, but all the military uses that. Heck, even Ham Radio operators use it.

quote:

Originally posted by GarandGuy:
“ A nautical mile is based on the circumference of the earth, and is equal to one minute of latitude. It is slightly more than a statute (land measured) mile (1 nautical mile = 1.1508 statute miles ). Nautical miles are used for charting and navigating.”

I just started taking flight lessons and getting exposed to knots. I'm back to converting the way I used to calculate 15% tips 30 years ago: move the decimal over 1, divide by two, add.

quote:

Originally posted by mikeyspizza:
"A nautical mile is based on the circumference of the earth, and is equal to one minute of latitude. It is slightly more than a statute (land measured) mile (1 nautical mile = 1.1508 statute miles )."

Is the 1.1508 statute miles derived from 1 minute of latitude at the equator? Or does it matter?

YES it matters.

quote:

Originally posted by mikeyspizza:
"A nautical mile is based on the circumference of the earth, and is equal to one minute of latitude. It is slightly more than a statute (land measured) mile (1 nautical mile = 1.1508 statute miles )."

Is the 1.1508 statute miles derived from 1 minute of latitude at the equator? Or does it matter?

I almost posted this last night.
Yes it matters. Each concentric latitude circle is divided into 360 degrees. As you move away from the equator each degree gets smaller and smaller the further you get from the equator.
Longitude lines are equal for lack of a better explanation. A degree is the same no matter which line it is measured on. This is why if using a printed nautical chart and you want to measure distance you use the scale given or use the longitude lines on the sides.
Yes I still use printed charts for trip planning. And I will always carry printed charts aboard.

Does the Navy or Merchant Marine still use leagues and cables?

League = 3 nautical miles (approx)

Cable = 200 yards (approx) or 1/10th of a NM.

quote:

Originally posted by Pyker:
Does the Navy or Merchant Marine still use leagues and cables?

League = 3 nautical miles (approx)

Cable = 200 yards (approx) or 1/10th of a NM.

Oh heck yeah we do/did; even made a submarine movie about being a certain amount of leagues under the sea.

Dropping buoys or navigating, it was a lot simpler to round off to 2000 yards and use 1.15 conversion when needed.

Seaman, I want you to go over and ask that chief petty officer for a bucket of prop wash because you've been assigned to mop the floor of this boat.

What I learned from this thread was the term "ring knocker" as I had never heard it before. Had to look it up.