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Jeff Jeff is offline
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First recorded activity by BoatBanter: Jul 2006
Posts: 1,301
Default Light Winds and extreme Tide Yesterday

Bart wrote:
"Jeff" wrote
Bart - it really sounds like you have the same misunderstanding of current
generated wind that Ellen did.

When you have zero true wind, but a strong current, there will be an
apparent wind that is indistinguishable from a real wind if you are not in
a position to detect the current. For example, it you are in the middle
of the ocean with no wind but a 10 knot current, that will feel exactly
like a 10 knot breeze. There would not be any weird affect like the
rudder having "no bite" and "losing control."


Not true Jeff. Think about it. Consider Case 1 and 3 below. Think
about a powerboat going down-river. A slow moving boat, say
just slightly faster than the current will have minimal control over
his steering. A boat drifting will have no steering. While a boat
moving much faster than the current will have good helm control.
Rudders don't work without water flowing by them. They work
by deflected the flow, not typically by sculling


All you're saying is that a boat not moving through the water has no
control, and a boat moving slowly has limited control. There is
nothing special because the apparent wind is caused by the current.

One reason why this is confusing is that the pure case I described
doesn't happen - it very rare to have enough current to sail on, and
when it happens its in constrained waters. And while 6 knots is a
huge amount of current, 6 knots of wind does not give you a lot of
maneuvering ability. I wouldn't want to go through Woods Hole on a
windless day, relying on the current to give enough speed to maneuver!

The one place I can think of where you could have some fun with this
is The Race at eastern Long Island Sound.



As for going faster than the current - if the boat can go faster than the
wind, which some do, then you can go faster than the current. But not
directly up or down current.


Agreed. But it would take an extremely fast boat--a typical boat would
not be able to do this. It is clear you could only hope to accomplish this
sailing across the wind. As I stated, you would still be better off sailing
into the current which would reduce your speed and give you more
control--in the typical currents you are likely to encounter.


No. Sailing into the current would be sailing downwind and you would
have the least control. Across the current would be reaching, and
down current wound be upwind.