Mt Whitney Zone Forums The Chat Room Jessica

wagga wrote:
> Cape Leeuwin is next, 4200 nm. away.

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

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?

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

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.

Thanks Alan. Because nanometer was truly the word being processed in my brain. I was SO CONFUSED!  

My mind was all out to sea. Need chocolate.

So she should have done the whole trip in a few msecs then?

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.

Proper units are over at El Reg, with some additional standards here.

And here is your Standards Converter.

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.

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

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

Abby is out to sea, so she is safe.

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.

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.

CNN's Hawaii coverage suggested 8 peaks in 4 hours, so a 30-minute period.

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?

Abby has reported in.

No problem.

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

CaT