Dave wrote:
Could you explain that? I would have thought that one NM is one NM
whether you're at the equator or the north pole.

Yes it is, but a minute of longitude differs in length as you go north
and/or south.


Wally wrote:
Not if there's a longitude component - the length of a minute of longitude
decreases as one moves away from the equator.

Exactly. So it would be imminently possible for (as Peter said) to go,
say, 100NM east, then turn and go 100NM north, then 100NM west, and
finally 100NM south, and end up west of where you started (in the
northern hemisphere). If you stretch the distance out more, you end up
in a different hemisphere. This would work on land, too, so you can't
blame leeway or the tide.

Fresh Breezes- Doug King

Dave,

A NM is 1/60 of a degree. A degree that is
360 divided into the length of the Equator. That is a NM anywhere. That
is a constant

A degree and a NM are equal at the Equator. A degree is only a constant
in measuring rotation with a circle being made up of 360 degrees. A
degree is not a linear measurement

OT

yes it does Thom,
I get it - well done!
Scout

"Thom Stewart" wrote
{snip}
I hope this help rather than confuse but I hope it helps explains the
problems of compass headings and expanding degree on a globe. It is a
concept worth getting a handle on.

Ole Thom

In most places where people are sailing, current would be
the greater effect.

Other factors, can all be lumped into something that for
lack of a better word is called current.

That is what I was taught.

DSK wrote

Yes it is, but a minute of longitude differs in length as you go north
and/or south.

"DSK" wrote in message
. ..

I was also suprised that nobody caught on to the diff in distance at
diff lattitudes... that was the first thing I thought of and was
surprised that it was not the point of the question.

The original question mentioned a distance of 14 miles. What do yuu think
that the maximum offset could be?




Regards


Donal
--

Last word ( Unless a special question for me.)
I was taught, any deviation for steered course was called "Drift" By
this discussion that may not be correct

Ole Thom

Donal wrote:

The original question mentioned a distance of 14 miles.

It specified hours and, later, constant speed. Still, we can assume 1kt and
ask ourselves...


What do yuu think that the maximum offset could be?

28nm.


--
Wally
www.artbywally.com
www.wally.myby.co.uk

Donal wrote:
The original question mentioned a distance of 14 miles.


I didn't see that. It looked to me like the speed & distance were
unspecified but assumed uniform on each leg.

Wally wrote:
It specified hours and, later, constant speed. Still, we can assume 1kt and
ask ourselves...



What do yuu think that the maximum offset could be?


28nm.

Is that with a really really bad compass

From my limited knowledge of, and ability with, spherical trig, I get
an answer of somewhere around 0.8 meters starting at the equator... now
I have another question, would the offset be constant as you move
further north or south?

I also find it curious that "The Navigator(tm)" had nothing to say on
this point.

Fresh Breezes- Doug King

I was taught that:

Speed is the forward motion through the water
Leeway is the sideways movement of the boat through the water
Current is the movement of the water over the ground
Steered course is the way you point
Sailed course is the direction that you move through the water
Course over the ground (is that called course made good ?) is the
direction you move over the ground
etc.

If one sails as you described in the question (on the northern
hemisphere), one sails toward a destination B that is west of the
starting-point A (if there were no current). The position after 56
hours is point C.
So, If your teacher taught you that when you sail from A toward B and
arrive at C then AC is the "current" then he must have been an
electrician and not a sailor. You could justify to call BC for
current, though the distance might be a result of more than just the
surface-waters movement over the ground.

Peter A/Y Anicula


"Bart Senior" skrev i en meddelelse
et...
In most places where people are sailing, current would be
the greater effect.

Other factors, can all be lumped into something that for
lack of a better word is called current.

That is what I was taught.

DSK wrote

Yes it is, but a minute of longitude differs in length as you go
north
and/or south.

It's a trivial academic exercise.

Bwhahahhahahahaha

Cheers

DSK wrote:



Donal wrote:

The original question mentioned a distance of 14 miles.



I didn't see that. It looked to me like the speed & distance were
unspecified but assumed uniform on each leg.

Wally wrote:

It specified hours and, later, constant speed. Still, we can assume
1kt and
ask ourselves...



What do yuu think that the maximum offset could be?



28nm.


Is that with a really really bad compass

From my limited knowledge of, and ability with, spherical trig, I get
an answer of somewhere around 0.8 meters starting at the equator... now
I have another question, would the offset be constant as you move
further north or south?

I also find it curious that "The Navigator(tm)" had nothing to say on
this point.

Fresh Breezes- Doug King