"Dave" wrote:

I'd call it course and speed made good..

Dave , you definitely will get 2 Anicula-points for your answer. And I
am very happy to see that someone seem to agree with me on this.

I suggested "Velocity over the ground ..." which I think is the same,
(I assume that velocity has both a direction and a size). I am not
really that familiar with your language, but I think that "course and
speed made good" sounds simple and on the point.

The other answer that I liked was Scouts "a Resultant" which I also
think would be right, though not saying much.

If one sails a variety of courses that would put you in new position
(different from your start-position) if there were no leeway, current
etc., I think it is absolutely crazy to call it set, current or a
tidal vector or any such thing.
A good navigator might not always end up exactly where he planned, but
the art of navigation demands that you use a clear and precise set of
conceptions, and that you use them right.

This is the reason for my ardent spirit on this subject, though ardent
spirits also might have something to do with it.

Peter S/Y Anicula

P.S. Are you familiar with a boat called "Ardent Spirit" - I think it
was owned by someone called Besser. That boat used to make me drool.

"Dave" wrote:
I'd call it course and speed made good..


Peter S/Y Anicula wrote:
Dave , you definitely will get 2 Anicula-points for your answer. And I
am very happy to see that someone seem to agree with me on this.

Oh yes, but I'm still a bit dazed by the question... it seems to me that
going around 4 sides of a large square is not really within the bounds
of VMG... usually 2 sides of a triangle are about the limit.

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.


I suggested "Velocity over the ground ..." which I think is the same,
(I assume that velocity has both a direction and a size). I am not
really that familiar with your language, but I think that "course and
speed made good" sounds simple and on the point.

Sure. Usually course made good and speed made good are two different &
seperate scalar entities. Velocity made good encompasses (pardon the
pun) both. VMG is usually thought of as the resultant speed toward an
upwind destination when tacking, or a downwind destination when reaching
back & forth; but it can just as easily apply any time you are not
heading directly toward your goal.

Fresh Breezes- Doug King

You do know the difference between tide and current?

Cheers

Donal wrote:

"Nav" wrote in message
...

You don't have currents? Here the currents typically run about 1 knot. I
think the gulf stream get up to about 4 knots.




I'm not impressed. I deal with currents up to 10 kts.

http://www.mistweb.force9.co.uk/content/solent1.html

Regards


Donal
--

Don-o,

We here in the Pac. NW deal with the same sort of Tidal Currents in the
Sound and Humbolt Current in the Ocean.

I know Mooron deals with the same thing in his area.

High Latitude sailors around the world all do

Ole Thom

Thanks Peter,
that's only because I don't know much. Can't let that stop me from jumping
in the water.
Scout

"Peter S/Y Anicula" wrote
{snip}
The other answer that I liked was Scouts "a Resultant" which I also
think would be right, though not saying much.

Thom,
the part I'm not getting is this: how do you know he's not back a the
starting point? I'm not saying you're wrong, just because I can't see the
logic in it, but I'd like to see the logic in it.
If we don't know how much distance he traveled on any leg, how come he can't
sneak up on the starting point again?
Scout

"Thom Stewart" wrote {snip}
The End of the trip, after 56 hrs wasn't at the starting position.

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.

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


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

Mr. President?
Scout

"Dave" wrote
It depends on what the meaning of "is" is g.

Scout,

He can't be at the starting point and be asking the name of the Vector
between the start and where he finished. Logical?

Also, even if there was no deviation due to Tidal drift, leeway etc,
just sail by "Timed Legs" on globe cannot make a square anywhere except
equal distance north & south of the equator or at the north or south
poles.

Scout, even if you sail a straight course you are sailing a curved line,
as far as elevation is concerned. This in itself will cause a course
change from East to South to be something different than a square corner
of a box.

Think of an ice cream cone, with the pointy end being north. Draw a
straight line from the lip of the cone to the tip (North) Now rotate the
cone 90 degrees and draw another line to the tip (North again) Now Scout
draw a line parallel to the lip of the cone, between those two lines. Is
it a square? Is it the same distance as the of the lip? It isn't is it?
Make it the same distance. Now, can you connect the ends with two
north---south lines to make a square?

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

Dave,

I too had trouble with the "Vector" but as the discussion has gone on,
vector just might be the right term

There has to be an angle back to the starting point as well as distance,
Both vector facters,

I'm not sure how you can say speed made good when we have no knowledge
of the distance or the speed of the trip. ( I believed he said constant
speed for the four legs)

What we have is Course heading and time of each of four legs.sailed on
an ocean. One question, a line(vector) drawn between the start and
completion without a name.

Ole Thom