Seems to me, a priori, that with a given rod and line, only one length
of cast (and therefore amount of casting effort) would achieve that. A
longer cast, or a shorter cast, would produce different results.

The resistance of the line will make the rod tip tend toward a straight
line. The more line is out, and the more mass is being accelerated, the
stronger the tendency.

Yes, that's what I was trying to say.

It's all according to the principle of least action...

Never heard of that. Can you explain? That's not another name for
Newton's First Law of Motion, is it? ((:-))

(which, by the way, is not the same "principle of least action"
that the Bush administration is following in the aftermath of Katrina).

No need to explain that one.

vince