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#2468 - 02/24/10 09:18 AM Re: Jessica [Re: wagga]
Steve C Offline


Registered: 09/22/09
Posts: 7833
Loc: Fresno, CA
wagga wrote:
> Cape Leeuwin is next, 4200 nm. away.

Ok Dave, what's the difference between km and nm?

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#2470 - 02/24/10 10:07 AM Re: Jessica [Re: Steve C]
wagga Offline


Registered: 10/07/09
Posts: 2249
Loc: Humbug Reach (Pop. 3)
A km. (kilometer) is 1000 meters (about .6 of a statute mile).
A statute mile is 1760 yards.
A nautical mile is 2000 yards, and a knot is 1 nm. per hour.

TMI?
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Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII

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#2478 - 02/24/10 02:39 PM Re: Jessica [Re: wagga]
CaT Offline


Registered: 09/24/09
Posts: 694
Loc: Blacklick, OH (formerly SoCal)
Or, as expressed in feet:

One mile (sm) - 5,280 feet
One kilometer (km) - 3,274 feet
One nautical mile (nm) - 6,000 feet

1 knot = 1.14 miles

CaT
_________________________
If future generations are to remember us with gratitude rather than contempt, we must leave them more than the miracle of technology. We must leave them a glimpse of the world as it was in the beginning, not just after we got through with it.
- Lyndon Johnson, on signing the Wilderness Act into law (1964)

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#2488 - 02/24/10 07:30 PM Re: Jessica [Re: Steve C]
AlanK Offline


Registered: 09/22/09
Posts: 583
Loc: Glendale, CA
Originally Posted By: Steve C
Ok Dave, what's the difference between km and nm?

Just in case Steve meant "nanometer" instead of "nautical mile", the difference is a factor of a trillion (American meaning of "trillion" not British).

That would mean that Cape Leeuwin was only 4.2 micrometers away!

Nerd humor. smirk

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#2490 - 02/24/10 08:48 PM Re: Jessica [Re: AlanK]
Steve C Offline


Registered: 09/22/09
Posts: 7833
Loc: Fresno, CA
Thanks Alan. Because nanometer was truly the word being processed in my brain. I was SO CONFUSED!   confused

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#2491 - 02/24/10 08:59 PM Re: Jessica [Re: Steve C]
wagga Offline


Registered: 10/07/09
Posts: 2249
Loc: Humbug Reach (Pop. 3)
My mind was all out to sea. Need chocolate.
_________________________
Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII

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#2498 - 02/25/10 12:26 AM Re: Jessica [Re: AlanK]
Mike Condron Offline


Registered: 11/05/09
Posts: 215
Loc: Now Manteca, CA
So she should have done the whole trip in a few msecs then?
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#2511 - 02/25/10 08:11 AM Re: Jessica [Re: Mike Condron]
AlanK Offline


Registered: 09/22/09
Posts: 583
Loc: Glendale, CA
Things would be easier if everyone would use proper units. For example, velocity would be expressed in furlongs per fortnight.

It goes without saying that there is a Wikipedia page on this subject. Unfortunately, Wikipedia seems to think it's all a joke. cry

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#2513 - 02/25/10 08:50 AM Re: Jessica [Re: AlanK]
wagga Offline


Registered: 10/07/09
Posts: 2249
Loc: Humbug Reach (Pop. 3)
Proper units are over at El Reg, with some additional standards here.

And here is your Standards Converter.


Edited by wagga (02/25/10 08:54 AM)
Edit Reason: Added Converter
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Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII

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#2553 - 02/27/10 06:54 AM Re: Jessica [Re: CaT]
Ken Offline


Registered: 10/29/09
Posts: 742
Loc: Los Angeles
Originally Posted By: CaT
Or, as expressed in feet:

One mile (sm) - 5,280 feet
One kilometer (km) - 3,274 feet
One nautical mile (nm) - 6,000 feet

1 knot = 1.14 miles

CaT


Not quite. A knot is a measure of speed, not distance. A nautical mile and a knot are not the same thing.

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#2557 - 02/27/10 10:44 AM Re: Jessica [Re: Ken]
KevinR Offline


Registered: 11/03/09
Posts: 595
Loc: Manchester, NH
Originally Posted By: Ken
Not quite. A knot is a measure of speed, not distance. A nautical mile and a knot are not the same thing.


Yup. My ice boat tops out at 50 knots, which is considerably faster than 50 mph.

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#2558 - 02/27/10 03:08 PM Re: Jessica [Re: KevinR]
CaT Offline


Registered: 09/24/09
Posts: 694
Loc: Blacklick, OH (formerly SoCal)
Quote:
Not quite. A knot is a measure of speed, not distance. A nautical mile and a knot are not the same thing.

Quote:
My ice boat tops out at 50 knots, which is considerably faster than 50 mph.

I understand a nm and a knot are not the same thing and that a knot is a mesure of speed and not distance. As a long time weather spotter for the NWS, I do know that the minimum criteria speed for wind to be "severe" in a severe thunderstorm is 50 knots, which is also the same as 58 mph. Obviously, distance is a part of how speed is calculated - thus, my less than perfect expression of 1 knot = 1.14 miles. I had original expressed this as 1 knot (per hour) = 1.14 miles (per hour), but resulting from a corrective comment made in a PM by another member here, I deleted the (per hour) notations shortly after my original post on this.

So since 50 knots = 58 mph, then it follows that 1 knot = 1.14 mph. I don't really desire to get into a technical discussion about this. My original "clarifying" post above was merely to try and express the various nm, sm, etc. in one common denominator (feet), to make it easier to understand.

CaT
_________________________
If future generations are to remember us with gratitude rather than contempt, we must leave them more than the miracle of technology. We must leave them a glimpse of the world as it was in the beginning, not just after we got through with it.
- Lyndon Johnson, on signing the Wilderness Act into law (1964)

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#2559 - 02/27/10 03:10 PM Re: Jessica [Re: CaT]
CaT Offline


Registered: 09/24/09
Posts: 694
Loc: Blacklick, OH (formerly SoCal)
To bring this thread back on topic, has anyone besides me wondered if and/or how the tsunami created by the 8.8 Chile quake this morning will affect Jessica?

I could only find a map showing the incremental wave dissemination throughout the main Pacific basin. But from that map, it appeared that the waves would also head out into the Southern Ocean (which is where the map cut off), which would eventually affect Jessica.

CaT
_________________________
If future generations are to remember us with gratitude rather than contempt, we must leave them more than the miracle of technology. We must leave them a glimpse of the world as it was in the beginning, not just after we got through with it.
- Lyndon Johnson, on signing the Wilderness Act into law (1964)

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#2561 - 02/27/10 03:39 PM Re: Jessica [Re: CaT]
wagga Offline


Registered: 10/07/09
Posts: 2249
Loc: Humbug Reach (Pop. 3)
Abby is out to sea, so she is safe.
_________________________
Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII

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#2562 - 02/27/10 04:38 PM Re: Jessica [Re: CaT]
wagga Offline


Registered: 10/07/09
Posts: 2249
Loc: Humbug Reach (Pop. 3)
Night has fallen in Chile.
The Jules Verne Trophy racer, is again, well out to sea, probably did not even notice the waves, which only get tall when they hit shallow water.

Mexico did see some effects.

Jessica is in the Indian ocean, so is safe.

Abby has a special message on her blog.

Commander Dilip is in harbor at Cape Town.
_________________________
Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII

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#2565 - 02/27/10 06:10 PM Re: Jessica [Re: wagga]
Mike Condron Offline


Registered: 11/05/09
Posts: 215
Loc: Now Manteca, CA
Plus I think the period of a Tsunami is quite long thus the low amplitude at sea. Many minutes as opposed to a normal swell which is way less than a minute like between 15 seconds to 30 seconds.

San Francisco Bay can get 6 foot swells with a 9 second period. The America's Cup could be interesting.
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Mike

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#2566 - 02/27/10 06:24 PM Re: Jessica [Re: Mike Condron]
wagga Offline


Registered: 10/07/09
Posts: 2249
Loc: Humbug Reach (Pop. 3)
CNN's Hawaii coverage suggested 8 peaks in 4 hours, so a 30-minute period.
_________________________
Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII

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#2574 - 02/27/10 11:22 PM Re: Jessica [Re: CaT]
Ken Offline


Registered: 10/29/09
Posts: 742
Loc: Los Angeles
Originally Posted By: CaT

I understand a nm and a knot are not the same thing and that a knot is a mesure of speed and not distance.
CaT


I wasn't really meaning to think that you didn't, but were using shorthand, which you were.
As a sailing instructor, I'm continually educationg people as to the meaning of the units, about which most people are confused. As a mathematician (statistics), I'm somewhat anal about keeping track of units in any discussion, to make sense of things.

It just jumped out at me as something that would be confusing, like stating that 1 mile = 60 minutes. Huh?

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#2575 - 02/28/10 06:43 AM Re: Jessica [Re: wagga]
wagga Offline


Registered: 10/07/09
Posts: 2249
Loc: Humbug Reach (Pop. 3)
Abby has reported in.
_________________________
Verum audaces non gerunt indusia alba. - Ipsi dixit MCMLXXII

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#2593 - 02/28/10 06:41 PM Re: Jessica [Re: Ken]
CaT Offline


Registered: 09/24/09
Posts: 694
Loc: Blacklick, OH (formerly SoCal)
No problem.

You're a sailing instructor?? What *don't* you do? smile
My brother-in-law took a series of courses for some level of sailing licensure (not sure what license it is).

CaT
_________________________
If future generations are to remember us with gratitude rather than contempt, we must leave them more than the miracle of technology. We must leave them a glimpse of the world as it was in the beginning, not just after we got through with it.
- Lyndon Johnson, on signing the Wilderness Act into law (1964)

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