The weather was beautiful yesterday, sunny and mild.
The wind was a little light if you considered the current
was the same strength.

There is more to Apparent Wind than True Wind plus
Boat Wind. There is also Current Wind.

Against the current and wind, the sailing was fine,
albeit a bit difficult to cover much ground. Fortunately,
if you knew where to avoid the current and where
you could fight it, the sailing was both interesting and
challenging.

Tidal range was about 9.5 feet. Max currrent was
dramatic and obvious. Still even an inexperienced
sailor could have fun.

Bart wrote:
....

Tidal range was about 9.5 feet. Max currrent was
dramatic and obvious. Still even an inexperienced
sailor could have fun.

Long Island Sound is interesting in that the tidal range varies from
2.3 feet in Noank to 7.4 feet in Greenwich.

Its like a big teetertotter, you can simply use gravity to slide from
one end of the sound to the other.

On a windless day, is it possible to drift with the current and use that
relative wind to power the boat faster than the current?

If so, could you go over why it is possible. I could never figure that one
out.

Thanks.

Jeff wrote:
Bart wrote:

Tidal range was about 9.5 feet. Max currrent was
dramatic and obvious. Still even an inexperienced
sailor could have fun.

Long Island Sound is interesting in that the tidal range varies from
2.3 feet in Noank to 7.4 feet in Greenwich.

Its like a big teetertotter, you can simply use gravity to slide from
one end of the sound to the other.

No kidding? Only 2.4 feet?

It's too bad that big mooring field off there is so
shallow. Then again, if the tide range was more
extreme people couldn't hook up there.

Gilligan wrote:
On a windless day, is it possible to drift with the current and use that
relative wind to power the boat faster than the current?

If so, could you go over why it is possible. I could never figure that one
out.

I don't think so, even though you could increase the
apparent wind at the expense of control.

Case 1: In the direction of the current:
You would be shoved along at the same rate and
your sails would hang limp. You would be "In Irons"

Case 2: Against the current:
The wind made by the current would push you slower
than the current, and you would still be forced in the
direction of the current. You would have no control
of your steering and at the mercy of the current.
Your speed would be the speed of the current less
any aerodynamic drag.

Case 3: Across the wind (90 degrees to the current):
You would be pushed at about a 45 deg angle "with
the current" and you would have to trim for a close haul. If
you tried to head up at all you would stall the boat
and go "In Irons" as in Case 1.
..
Your Boat Wind would be less than the Current Wind,
however, combine the two and the Apparent Wind would
be slightly greater than the Boat Wind. Could the boat
then sail faster than the Boat Wind or Current Speed?
I think in a light boat in might be possible. But the
difference if any would be negligable. In most boats
your speed would be less because of drag.

Clearly, this direction would give you your best boat speed,
but since you are now moving in roughly the same direction
as the current your helm response would be horrible. Who
would want less control in avoiding obstacles "down current"?

Case 4: 45 degrees into the current:
This should give you roughly beam reach sail trim, and
the boat would be moving slightly in the direction of the
current. In this case the vectors cancel somewhat and
your Apparent Wind would be less than the Current Wind.
You would be able to avoid obstacles and steer better as you
would have good flow across your rudder. This would get you
away from a dock--in slow motion, and away from danger with
the most control. Your boat would still be moving down current
while making the best possible speed away from a dock or shore.

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."

The only weirdness would be if you tried to dock the boat or pick up a
mooring - it would act as if it were going by at 10 knots.

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.


Bart wrote:
Gilligan wrote:
On a windless day, is it possible to drift with the current and use that
relative wind to power the boat faster than the current?

If so, could you go over why it is possible. I could never figure that one
out.

I don't think so, even though you could increase the
apparent wind at the expense of control.

Case 1: In the direction of the current:
You would be shoved along at the same rate and
your sails would hang limp. You would be "In Irons"

Case 2: Against the current:
The wind made by the current would push you slower
than the current, and you would still be forced in the
direction of the current. You would have no control
of your steering and at the mercy of the current.
Your speed would be the speed of the current less
any aerodynamic drag.

Case 3: Across the wind (90 degrees to the current):
You would be pushed at about a 45 deg angle "with
the current" and you would have to trim for a close haul. If
you tried to head up at all you would stall the boat
and go "In Irons" as in Case 1.
.
Your Boat Wind would be less than the Current Wind,
however, combine the two and the Apparent Wind would
be slightly greater than the Boat Wind. Could the boat
then sail faster than the Boat Wind or Current Speed?
I think in a light boat in might be possible. But the
difference if any would be negligable. In most boats
your speed would be less because of drag.

Clearly, this direction would give you your best boat speed,
but since you are now moving in roughly the same direction
as the current your helm response would be horrible. Who
would want less control in avoiding obstacles "down current"?

Case 4: 45 degrees into the current:
This should give you roughly beam reach sail trim, and
the boat would be moving slightly in the direction of the
current. In this case the vectors cancel somewhat and
your Apparent Wind would be less than the Current Wind.
You would be able to avoid obstacles and steer better as you
would have good flow across your rudder. This would get you
away from a dock--in slow motion, and away from danger with
the most control. Your boat would still be moving down current
while making the best possible speed away from a dock or shore.

"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

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.

Bart wrote:
Gilligan wrote:
On a windless day, is it possible to drift with the current and use that
relative wind to power the boat faster than the current?

If so, could you go over why it is possible. I could never figure that
one
out.

I don't think so, even though you could increase the
apparent wind at the expense of control.

Case 1: In the direction of the current:
You would be shoved along at the same rate and
your sails would hang limp. You would be "In Irons"

Case 2: Against the current:
The wind made by the current would push you slower
than the current, and you would still be forced in the
direction of the current. You would have no control
of your steering and at the mercy of the current.
Your speed would be the speed of the current less
any aerodynamic drag.

Case 3: Across the wind (90 degrees to the current):
You would be pushed at about a 45 deg angle "with
the current" and you would have to trim for a close haul. If
you tried to head up at all you would stall the boat
and go "In Irons" as in Case 1.
.
Your Boat Wind would be less than the Current Wind,
however, combine the two and the Apparent Wind would
be slightly greater than the Boat Wind. Could the boat
then sail faster than the Boat Wind or Current Speed?
I think in a light boat in might be possible. But the
difference if any would be negligable. In most boats
your speed would be less because of drag.

Clearly, this direction would give you your best boat speed,
but since you are now moving in roughly the same direction
as the current your helm response would be horrible. Who
would want less control in avoiding obstacles "down current"?

Case 4: 45 degrees into the current:
This should give you roughly beam reach sail trim, and
the boat would be moving slightly in the direction of the
current. In this case the vectors cancel somewhat and
your Apparent Wind would be less than the Current Wind.
You would be able to avoid obstacles and steer better as you
would have good flow across your rudder. This would get you
away from a dock--in slow motion, and away from danger with
the most control. Your boat would still be moving down current
while making the best possible speed away from a dock or shore.

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.

Jeff wrote:
Bart wrote:

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.

Sailing into the current would give you the more control
because you would have the more flow across the
rudder. You would be moving backwards, as the current
drove you down current, but relative to the water you would
be making way forwards or at some angle to down current.
As I pointed out 45 deg to down current would be the best
choice.

You would not want to go directly into the current as in this
case you would surely be moving backwards and only able to
change the direction the boat was pointing. It would be better
to sail at an angle of about 45 degrees to the current with an
apparent wind beam reach course if you were leaving a dock.
This would get you clear of obstacles down current, because
you would still be forced down current.

On 9 Oct 2006 05:38:23 -0700, "Bart" wrote:

The weather was beautiful yesterday, sunny and mild.
The wind was a little light if you considered the current
was the same strength.

There is more to Apparent Wind than True Wind plus
Boat Wind. There is also Current Wind.

Against the current and wind, the sailing was fine,
albeit a bit difficult to cover much ground. Fortunately,
if you knew where to avoid the current and where
you could fight it, the sailing was both interesting and
challenging.

Tidal range was about 9.5 feet. Max currrent was
dramatic and obvious. Still even an inexperienced
sailor could have fun.

You can more fun in Wales, boyo!
http://www.canoewales.com/far_west/bitches_frame.htm