"Wayne.B" wrote in message
...
On Tue, 6 Apr 2010 10:37:46 -0700, "nom=de=plume"
wrote:

"Wayne.B" wrote in message
. ..
On Mon, 5 Apr 2010 19:12:53 -0700 (PDT), Frogwatch
wrote:

My 28' sailboat is now in Stuart, Fl after transiting the Okechobee
waterway but I want to get to Bimini and then to the Berry Is. so I
need to get to Miami. However, I am now very tired of the ICW so I
would like to sail down the coast on the outside from Stuart to
Miami. If I stay within 5 miles of land, will I have any problems
with the Gulf Stream pushing me N.?

You can minimize the current by staying right along the beach in 20 to
30 ft of water but you will still have half a knot or so against you
in many places.

This is due to the smaller volume of water (shallow vs. deep)? Or is
something else going on?

It's a combination of being as far away from the center axis of the
stream as possible, combined with the friction/constriction of shallow
water along the shore.


Center axis or mid-point (both vertically and horizontally would be an
issue), so the axis must be in the center of the channel. But... the axis
would have to be offset proximal to the surface, since the seabed at center
channel would have less friction than the sea surface (air).

So, where the water is the most shallow, there is greater surface friction
on the seabed. I understand that. So with regard to the constriction
portion, it seems like that would be a back-eddy or countervailing current
to the main flow. Water isn't usually considered as compressible, so that
can't be it. It seems like the friction and the backflow are the key
factors. I wonder which one is more significant.

The factor that would lower the axis seems to depend on "sea state" (e.g.,
storm conditions), since would create more back-eddy (at the surface) and
perhaps significant waves would increase friction due to increase in
friction.

--
Nom=de=Plume