it was a well posed mathematical problem.

jeffie, the assumptions were just assumptions, therefore the answer can be no
more accurate than the product of the least accurate assumptions.

You
ignored the complicating issue and solved a simpler case.

There was no complicating issue. It was nothing but assumptions to start with.
I dealt with the simpler case of a 90* shift in course rather than a 100*
shift because while the concept was unchanged, the math became more simple and
thus did not stand out from its rightful place in the background.

You were 10% off in
the speed and 5 degrees off in the current direction.

there was no speed and no direction. It was just a question as to "how could
it happen?". you solved precisely to arrive at a vagueness.

You the ignored the
second part because it required some actual math.

I left the second part because it came to the same conclusion.


Donal solved both problems
using a proper navigational method,

there is no "proper navigational method", for the question was "how could it
happen?"

though I think his accuracy could have been
better.

you mean his *precision* could have been better. His accuracy could not
improve because the problem started with inaccurate data.

I simply provided the proper mathematical solution.

there is not "proper mathematical solution" to assumptions.

I sorry if a bit of trig is
beyond you.

beyond me? *you* were the one who didn't notice the trig was still there, but
presented in a fashion to keep it in the background where it belonged.

BTW, given the numbers you provided, why do you think this was "an eddy" and
not
the Gulf Stream itself?

because, the shift to an eastward course happened quickly enough so that the
"averaging" algarithm on two gps's -- each from a different manufacturer --
caught the course change at the nearly the very same instant. I looked up to
say my gps went idiotic maybe a half second before the other guy looked to say
the same thing of his gps. the Gulf Stream would have to very dramatically
change course in a very short period of time. Eddies, on the other hand, do
form quickly and are much smaller so it is easier to sail in or out of one in a
short distance. Keep in mind that we did not change our heading, nor did we
notice a change in cloud position relative to the mast/sails.