"Jeff" wrote in message
...
jlrogers±³© wrote:
"Shaun Van Poecke" wrote in message
...
Here's one for those of you out there without onboard
instruments/knotmeter/gps....

Is there any reasonably accurate (say, within a know or so) way of
judging the current, when you are under way, and there are no fixed
objects within sight?

Yes, Shaun, there is. For your edification, I refer you to, "We, the
Navigators The Ancient Art of Landfinding in the Pacific," by David
Lewis. Specifically chapters 5, "Keeping course by Sun, Swills, and
Wind," chapter 6, "Dead Reckoning," which directly addresses your
question, and chapter 7, "Orientation Concepts in Dead Reckoning."

http://books.google.com/books?vid=IS...H54BfXwOv1l5Zs

Ah! One of my favorites books! Thanks for the mention, I think it may be
time to read it again!

However, I don't think it supports your position. For instance, in the
chapter on Dead Reckoning, it begins the section on Current Set with "This
presents a difficult and intractable problem of which the Pacific Island
navigators were only too well aware ..." It goes on to describe how they
memorized all of the currents, and then took careful back bearings on
departure to determine how the currents were deviating from the expected
norm.

The traditional navigators did make use of a variety of signs, such as the
steepness of waves (as I mentioned in another post) but I doubt the casual
Western observer could reliably use these sign to measure to within a
knot.


True, but with "enough experience" a bow wave will tell one the speed of the
boat through the water. Wind judgment with knowledge of your boat will tell
you what your speed ought to be sans current. The difference is the
current.

--
jlrogers±³©