# nautical miles & regular miles?

KJP Guest

hey,

I was just wondering is there a difference between regular milage in say your car and nautical miles as in FS2004?

cheers

KJP

Jonathan (99jolegg) Chief Captain
Don Wood Guest

To convert Nautical Miles to Statute Miles, multiply nautical miles by 1.1507794 (I normally round that to 1.151).

To convert Statute miles to Nautical miles, multiply statute miles by .8689762 (I round to .869)

nottobe Captain

to make life easier, the metric system should be in use throughout the world

Matthew Shope (mypilot) Chief Captain

I agree. If the whole world just simply went to metrics then kids (like me) would only have to learn one system of measuring. That reminds me of last month. We were in math and so we were talking about metrics and U.S. measurments so my friend asks the teacher, "So how old would I be in metrics?"

If the whole world went to metrics everything would be simpler. They are easier than the current U.S. measurments. Because in metrics it is usually 10=1. i.e. 10 milimeters=1 centemeter and 10 cm=1 Decimeter.

Guest Ed Guest

nottobe wrote:

to make life easier, the metric system should be in use throughout the world

It is in use throughout the world. Only a few stubborn 'Mericans are holding out, and forcing countries which sell to us (and the few which still buy from us) to continue using our obsolete system.

Ed

COLINR Trainee

Guest Ed has obviously never driven in the UK all road signs are in Imperial miles

Steve (megafoot) First Officer

Knots and Nautical miles are good old navy terms. The nautical mile was based on the circumference of the earth at the equator. Since the earth is 360 degrees of longitude around, and degrees are broken into 60 so-called "minutes", that means there are 360 * 60 = 21,600 "minutes" of longitude around the earth. This was taken as the basis for the nautical mile; thus, by definition, 1 minute of longitude at the equator is equal to 1 nautical mile. So the earth is ideally, by definition, 21,600 nautical miles (and 21,600 "minutes" of longitude) in circumference at the equator. If anyone ever asks you how far is it around the earth, you can quickly do the math in your head (360 degrees * 60 minutes per degree) and answer "about 21,600 nautical miles"!

In fact, even modern navigators use the "minute of latitude" on charts to measure distance; this is what you see them doing when they use their compass spreaders while they are hovering over their nautical charts (maps). [For geometrical reasons, we use the minute of latitude on charts to correspond to a nautical mile rather than the minute of longitude. Minutes of longitude shrink as they move away from the equator and towards the poles; minutes of latitude do not shrink. Take a look at a globe with longitude and latitude lines marked on it to understand why.]

Using the definition of a nautical mile for distance at sea, the challenge was to measure speed -- i.e. what is the ship's speed in nautical miles per hour? (By the way, the nautical mile is about 1.15 larger than the "statute" mile used by land lubbers.) Since [speed] = [distance] divided by [time], if we measure a small distance (or length) in a small time we can do the math and figure our speed.

The device that sailors used to make their speed measurement was called the "chip log". Chip as in chip of wood, and log as in to record in a log. The chip was a wedge of wood about 18" in size; it was tied to one end of a rope on a large spool. The rope had knots tied into it about every 47'3" (more about how that was calibrated below).

The wooden chip was thrown overboard at the ship's stearn (back end). Because of its wedge shape, it would "grab" the water and start pulling out rope as the ship moved forward at some yet unknown speed. One man would hold the spool of rope as it played out; another man would start a sandglass filled with 30 seconds of sand; and a third man would count the knots as they passed over the stearn board. When the 30 seconds of sand expired, the time keeper would call out and the counting of knots would stop.

The faster the ship was sailing, more knots and a longer length of rope were played out. The number of knots in the rope that were counted in 30 seconds, then, was equal to the speed of the ship in nautical miles per hour. A "knot", therefore, is not a nautical mile, it is a nautical mile per hour. Thus 1 knot was equivalent to 1 nautical mile per hour; 5 knots were equivalent to 5 nautical miles per hour; etc. The similar sound of "knot" and "naut" is entirely coincidental.

Finally, what about the actual values of 47'3" between knots on the rope and the 30 seconds that were used with the chip log? The length was based on converting [1 nautical mile per hour] to [feet per second(fps)], and then multiplying [fps] by 30 seconds (which was a practical time to spend counting knots with a sandglass). The result was the calibrated length in feet at which to tie the knots for a 30-second run of the chip log.

... Now that we have much more precise technology to measure things, and because we need to establish international standards and conversion factors, and because the earth is not uniformly flat or round anywhere, and because even the precise definition of the second has changed, the official value for how many international feet in an international nautical mile has changed. Likewise, the measuring time of about "30 seconds" in the sandglass is now calibrated at 28 seconds. Time itself didn't change by 6.7%! But the cumulative effects of new international standard definitions for time, feet, statute miles, and nautical miles and more accurate measurements of the actual size of the earth -- and the fact that we don't use sand to measure time anymore -- have changed the modern calibration of the chip log.

data collected from:
http://www.onlineconversion.com/faq_07.htm

Guest Ed Guest

COLINR wrote:

Guest Ed has obviously never driven in the UK all road signs are in Imperial miles

Actually, Guest Ed has driven in the UK but it was a very long time ago, and the road signs were indeed in miles. I was there when you folks went from pounds, shillings and pence (talk about a confusing system: exactly what is a guinea?) to pounds and new pence, if that gives you some idea.

This whole business of SI versus "Imperial" units is kind of a sore point with me, because I am a measurement professional, a "metrologist." I've worked in calibration labs, standards labs, inspection labs, and now an optical engineering department, all my life, always making measurements. I can work in any system of units, but I prefer to work in SI units because it makes life simpler for everyone involved. I just don't understand the reluctance of my countrymen to change.

BTW, on this side of the pond we refer to them as "traditional" units or sometimes "english" units, but usually not "Imperial."

Ed

mickwill Trainee

I Have to post on this one - Whats wrong with Pounds Shillings and Pence?

It's really very simple!

2 Farthings = 1/2 Pence
4 Farthings = 1 Penny
12 Pennies = 1 Shilling
5 Shilling = 1 Crown
20 Shillings = 1 Pound

Coins - Farthings (1/4 pence), Ha'peeny (1/2 Pence), Penny, Thrupenny bit (3 Pence), Shilling (12 Pence or a 'Bob') , Half-Crown (2 Shillings and six pence/'Half a Dollar'), Crown (5 shillings or Dollar), 10 Shilling Note, Pound Note (20 shillings).

Right got that straight?

A guinea is £1 and 1 Shilling, it has never existed as a coin or note but was used to express the cost of an item, usually by the more upper-crust establishments. For example the orginal Baird Televisor (that's TV to the younger guys) sold on Oxford street in the late thrities for 5 Guineas, or 5 pounds (L) and 5 Shillings (S) and 0 Pence (D)

L for pounds (Libra)
S for shillings (Solidus)
D for pence (Denarius)

Bet you wished you'd never asked

Cheers

Mick

Guest Ed Guest

mickwill wrote:

I Have to post on this one - Whats wrong with Pounds Shillings and Pence?

It's really very simple!

2 Farthings = 1/2 Pence
4 Farthings = 1 Penny
12 Pennies = 1 Shilling
5 Shilling = 1 Crown
20 Shillings = 1 Pound

Coins - Farthings (1/4 pence), Ha'peeny (1/2 Pence), Penny, Thrupenny bit (3 Pence), Shilling (12 Pence or a 'Bob') , Half-Crown (2 Shillings and six pence/'Half a Dollar'), Crown (5 shillings or Dollar), 10 Shilling Note, Pound Note (20 shillings).

Right got that straight?

A guinea is £1 and 1 Shilling, it has never existed as a coin or note but was used to express the cost of an item, usually by the more upper-crust establishments. For example the orginal Baird Televisor (that's TV to the younger guys) sold on Oxford street in the late thrities for 5 Guineas, or 5 pounds (L) and 5 Shillings (S) and 0 Pence (D)

L for pounds (Libra)
S for shillings (Solidus)
D for pence (Denarius)

Bet you wished you'd never asked

Cheers

Mick

Mick, thank you for that educational lecture. I've had all that explained to me a few times, but it never seems to stick. Fortunately, now all I need to know is 1 pound = 100 new pence. Or are you using Euros now?

Regarding the coins: what about the six pence?

I actually did know the value of a guinea (having attempted to purchase a few items in the "upper crust" establishments you mention). I just never understood why it was used. Why price all the items in a store in a non-existent unit of currency? Just to discourage people who are mathematically-challenged???

Ed

jaapverduijn Trainee

"(...) what about the six pence? (...)"

Ah, the good old "zac"!

Jaap Verduijn.

mickwill Trainee

In common usage, a guinea is 21 shillings - much used in auctions (the bidder pays in guineas, the vendor gets paid the same number of pounds - the auctioneer gets the rest) and as the prizes (and names) for horse races. The guinea was introduced in 1663, made in gold obtained from Guinea (Ghana) in Africa, its value being fixed at 21s in 1717 (before that date its value depended on the current price of gold). Coins of 5, 2, 1, ½, one-third and ¼ guineas were issued up to George III (most finished in 1813).

So to pay in Guineas was seen to meanyou were a wealthy person.

Just for the record I'm not old enough to remeber pre-decimalisation

Here endeth todays history lesson - next week Latin for beginners

rifty Trainee

Lovely driving a car in England - buying your petrol in litres thanks to EU regulations and travelling distance in miles.

Try working out your damn miles per gallon on your company car expense sheet with all that.

Personally, I prefer buying liquids that come by the Keg or the Firkin. (Beer for all the furriners here!!)

Guest Ed Guest

rifty wrote:

Lovely driving a car in England - buying your petrol in litres thanks to EU regulations and travelling distance in miles.

Try working out your damn miles per gallon on your company car expense sheet with all that.

Personally, I prefer buying liquids that come by the Keg or the Firkin. (Beer for all the furriners here!!)

There are a few of those English beers commonly available in the bars here in California; I usually see Bass Ale and Newcastle Brown Ale. Not cheap, though-- a restaurant near me charges \$5.00 (~2.75 Pounds?) for a pint of Newcastle!!

The-GPS-Kid, if you're reading this, how much does a pint of Newcastle Brown Ale sell for in Newcastle?

Ed

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