Next message: Trevor J. Kenchington: "Global oceanic tides, was: Navigating Around Hills and Dips in the Ocean"
I can't claim to speak for all mariners out there today, but in my
experience and studies gravitational fields were never considered directly
as a factor in planning passages. I'm sure the Admiralty would have devoted
a chapter to it in their 'Ocean Passages' publication had it been a factor
of importance.
While I won't pretend to be in the same scientific class as some of the
members here, I would say that Mr. Huxtable's input on this seem to make the
most sense. But even if he's wrong, and you could go 'downhill' at sea,
ultimately this discussion is futile as to the question (paraphrased):
"Would ships benefit from planning a 'downhill' voyage based on the
gravitational data?"
If we assume a voyage of 7000km, with a difference in height of about 200m
between the gravitational lows and highs, the downhill angle will be in the
order of thousandths of a degree, and the 'extra downhill force' is
negligible relative to the total effort needed to keep the ship moving.
That's about as scientific as I can get on this, so if I made a error in
calculation or logic, I'm sure I will hear about it.
Still enjoying the list as a great way to stimulate the brain,
Rino
P.S. Of course I have no problem with sailing on Friday the thirteenth, but
I would definitely be extra careful...
