Brain teaser revisited
Thu, 26 Aug 1999 17:24:13 EDT

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West Wight Potter Website at URL
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In a message dated Thu, 26 Aug 1999 2:19:51 PM Eastern
Daylight Time, "Eric Johnson" <> writes:

> The same argument, unfortunately, shows that its impossible
to sail upwind
> at all. We know thats untrue.
> at all times I was discussing the issue sincerely. My take:
Any time the
> water and wind are at different velocities, you have
apparent wind and can
> sail. If your boat can make way to weather, it can go
anywhere. If you are
> in still water and can make good any windward velocity with
2k wind, its
> doable. Windspeed over ground means nothing - we're not on
the ground.
> For the same reasons, you could fly a kite in no true wind
from the same
> drifting sailboat, given enough current.
> I've actually got some diagrams and props that make that
> situation easy to understand, but explaining in email is
difficult and
> frankly I don't care if you agree or anyone agrees with me.
Actually, in the
> discussion, i think we were talking still air and a 2K
current - its
> unlikely most any boat could make a lot of way with such
little apparent
> wind and any leeway, but given the right circumstance (make
it say a 7k
> current) it ought to be doable.
> >to make a
> > passage or to pursue their dreams they would be in
> Yeah, I'm sure lots of folks have a dream of outrunning a
river current in
> still air :-P

Jim wrote:

> >I have
> > yet to see
> > proof from anyone if such a feat is possible.

Hey guys, such a feat is indeed possible.

I've done it. Along with dozens of other people at ABK's
windsurfing training camps in the Sacramento River Delta.
Done it several years in a row. In dead are and a flood tide
on the river of 4+ knots. We typically sailed 4-5 miles
"downstream" in about an hour.

The "feat" is followed that night with a lecture and video
entitled "We all sail on apparent wind", subtitled "How to
win a race when there's no wind or lots of lulls".

There's a very noticable difference between floating
downstream on a windsurfer compared to sailing downstream.

When there's no wind, you have to hold the sail up and it's
hot, tiring sweaty work. When there's a little wind, the
sail holds itself up and you grip the boom and lean back to
counter balance it -- and it's fun. When it's really windy,
you need a harness and footstraps to keep yourself from being
lifted off the board by the sail -- than it's an adrenaline

We had fun on those "windless" downwind runs. There was
enough apparent wind to hold the sails up so we didn't have
to work at it. And while we weren't sailing really fast, it
was fast enough to be fun.

Jim, if you doubt my story, or just want collaboration, call
ABK Windsurfing Camp in the SF Bay area and ask to speak to
the head coach or one of the assistant coaches. These guys
are former olympic and world champions and they know more
about sailing than those hydrodynamicists who gave you their
so-called expert opinions on sailing.

Judy B