Just ignore crapton.

That sounds rough... Sounds like a combination of bad judgement on the part
of the skipper and the guy who got hit. We typically sail in 25+ kts, and
rarely use a preventer unless we're going to have a long downwind run. We
don't race though.

--
"j" ganz @@
www.sailnow.com

"rhys" wrote in message
...
On Sun, 21 Nov 2004 16:30:46 -0800, "Jonathan Ganz"
wrote:


For either the slow, stupid, or stunned, it's called the boom boom.

We had a regatta in my club in 2001 during which a fellow was killed
via "boom boom". A storm front went through creating 50 knot winds
that...unusually...stayed at 30-35 knots most of the day even as the
sun came out. During the races, a poor ******* got clipped in the
head...hard...during a crash jib (no preventers or concept of "duck",
I assume). He failed to fall down and got smashed on the opposite side
of the head a couple of seconds later.

They pulled the plug on him after a week in a flatline coma.

Even though I recall the boat was a C&C 29, the motion was so fast and
hard that even that boat's 10 foot boom had enough velocity to crunch
a skull.

So use preventers and watch sea-state roll in downwind situations.

R.

On Mon, 22 Nov 2004 13:30:55 -0800, "Jonathan Ganz"
wrote:

Just ignore crapton.

That sounds rough...

It was. A couple were drowned when their catamaran flipped down by
Windsor in the same wind front. Several boats were damaged (it was a
C&C regatta) and I saw a 41 footer attempt to get inside our basin at
the height of it...the water was pouring OUT of the basin so fast they
had to come about and run out into the lake.

Sounds like a combination of bad judgement on the part
of the skipper and the guy who got hit.

Or he was 6' 2". The seas were high and got higher all day as the wind
swung west. Even at dock it was reading 35 knots...we stayed in due to
traffic and my wife's advanced state of pregnancy.

We typically sail in 25+ kts, and
rarely use a preventer unless we're going to have a long downwind run. We
don't race though.

I rig preventers frequently but leave them slack unless conditions
warrant it. But then I sail my 33 footer solo a lot and I am about one
inch taller than the boom end if the mainsheet is taut.

R.

Using the sail's trailing edge as a leading edge is problematic.
They will not be efficient this way - tantamount to running an
airplane wing backwards.

Letting them out on the port side however would work provided
you could let them out that far without fouling the rigging.

CN


"Love a Sheep" wrote in message om...
I am learning to sail and have a few questions. I understand that the
sails can act either as an airofoil (lile an aircraft wing) or like a
parachute where the wind simply blows the sail directly. My question
is this. If the wind is ahead of the beam ie we are sailing windward
then I expect that the airofoil principle must always hold there
otherwise we would be sailing backwards!

However, if the wind is aft of the beam on say the starboard side then
surely we have a choice where to set the sails ie they can be on the
starboard side (ie the boom is pointing to the starboard side) where
they act as an airofoil or on the port side where they act as a
'parachute' - is this right or am I missing something. If so which is
best?

Thanks

On Sun, 21 Nov 2004 12:18:14 -0800, Love a Sheep wrote:

I am learning to sail and have a few questions. I understand that the
sails can act either as an airofoil (lile an aircraft wing) or like a
parachute where the wind simply blows the sail directly. My question
is this. If the wind is ahead of the beam ie we are sailing windward
then I expect that the airofoil principle must always hold there
otherwise we would be sailing backwards!

However, if the wind is aft of the beam on say the starboard side then
surely we have a choice where to set the sails ie they can be on the
starboard side (ie the boom is pointing to the starboard side) where
they act as an airofoil or on the port side where they act as a
'parachute' - is this right or am I missing something. If so which is
best?

Thanks

You've already got a lot of good answers. I'll just point out one more
thing which is that the two sails on a boat interact. That is, even when
the wind is aft of abeam, the wind flowing over the main may be dead abeam
or so, because the jib or spinnaker changes the direction of flow.

--Mac

(Love a Sheep) wrote in message . com...
I am learning to sail and have a few questions. I understand that the
sails can act either as an airofoil (lile an aircraft wing) or like a
parachute where the wind simply blows the sail directly. My question
is this. If the wind is ahead of the beam ie we are sailing windward
then I expect that the airofoil principle must always hold there
otherwise we would be sailing backwards!

However, if the wind is aft of the beam on say the starboard side then
surely we have a choice where to set the sails ie they can be on the
starboard side (ie the boom is pointing to the starboard side) where
they act as an airofoil or on the port side where they act as a
'parachute' - is this right or am I missing something. If so which is
best?

Thanks
Once the wind if aft of the beam the generally accepted rule if to
have the boom at right angles to the wind. Likewise when you pole out
the headsail.

(Love a Sheep) wrote in message . com...
I am learning to sail and have a few questions. I understand that the
sails can act either as an airofoil (lile an aircraft wing) or like a
parachute where the wind simply blows the sail directly. My question
is this. If the wind is ahead of the beam ie we are sailing windward
then I expect that the airofoil principle must always hold there
otherwise we would be sailing backwards!

However, if the wind is aft of the beam on say the starboard side then
surely we have a choice where to set the sails ie they can be on the
starboard side (ie the boom is pointing to the starboard side) where
they act as an airofoil or on the port side where they act as a
'parachute' - is this right or am I missing something. If so which is
best?

Thanks

You can't really put both of your sails to what in your description
would be the windward side of the boat...well, not effectively at
least. here's why....

Unless you're sailing dead downwind (wing and wing, or by the lee, as
mentioned - boom toward the VERY slight widward side, also as
mentioned) you'll notice that no matter how far out you let your sails
when on an actual port or starboard tack, you're always going to have
the airfoil effect, not a parachute effect. Watch your telltails,
you'll see the wind moving across the sails, leading edge to trailng
edge. In your case, if the wind was from starboard, even fairly
significantly abaft the beam, you would still sail on starboard tack,
sails trimmed out to port. Once this becomes impossibly, it's either
time to jibe, or go wing and wing.

To relate this to a plane, think about the apparent wind when they
slow down to land and they 'set' the flaps to create much more 'belly'
in the wing to maintain that lift as the wind direction changes
(remember, apparent wind...of course, they're still going forward,
but the plane wants to fall, so the wind direction is now coming from
further under the wing, less in front of it, so they have to adjust,
just like you do) But there's no way a wing will act as a parachute on
a plane, it's still an airfoil. Same thing you're doing with your
sails. The difference is in the fact that a plane can also adjust it's
apparent wind direction by adjusting its speed. But the adjustments
are based on the same principle. If the plane went too slow, it would
fall of course, luckily, we don't have to worry about that, and when
the wind is directly behind us (i.e. the minimal amount of apparent
wind) - we CAN use the parachute effect. but it's only in that
scenario.

how's that for a long drawn out explanation! Sorry for the verbose
detail...hope it made even a bit of sense!

P.S. And yes, be careful sailing downwind wing and wing...accidental
jibes are not your friend. if you're going to do it for long, pole
out, and rig preventers, especially in rolly seas.

Good luck!

Capt. Rob Welling
Sarasota, FL

The airfoil is there in all cases, in this respect; as the sail aqttacks the
wind, reguardless of the angle, some air flows on both sides of the sail.
Wind flowing over the most leeward side of the sail creates a partial vacume
on that side, so with air pressure stronger on one side the sail is
"pushed" or "drawn" to the direction where the low pressure is.
Even with the wind directly astern, a low pressure is created on the front
of the sail, and the sail(boat) is drawn forward. Hope that is as clear as
I mean it to be. Welcome to the intoxicaion of sailing.

Dave Hord.

On Wed, 09 Feb 2005 08:49:14 GMT, "DAVE HORD"
scribbled thusly:

The airfoil is there in all cases, in this respect; as the sail aqttacks
the
wind, reguardless of the angle, some air flows on both sides of the sail.
Wind flowing over the most leeward side of the sail creates a partial
vacume
on that side, so with air pressure stronger on one side the sail is
"pushed" or "drawn" to the direction where the low pressure is.
Even with the wind directly astern, a low pressure is created on the front
of the sail, and the sail(boat) is drawn forward. Hope that is as clear as
I mean it to be. Welcome to the intoxicaion of sailing.

Dave Hord.



OK, that's Bernoulli.

Now I'd suggest you look into Newtonian explanation of lift
ie deflection.


Oz1...of the 3 twins.

I welcome you to crackerbox palace,We've been expecting you

It is a simple matter to derive "Bernoulli" using Newtonian equations and
principals. They are the same thing. One common mistake people have with
Bernoulli is using scalar speed and not vector velocity. If you use scalar
speed, Bernoulli is then only valid in "one" dimensional flow like that
approximated in pipes. Pipe flow observations is what Bernoulli used to
formulate his equations.

Mark

"Capt. Mooron" wrote in message
news:bqKOd.17903$K54.4882@edtnps84...
On Wed, 09 Feb 2005 08:49:14 GMT, "DAVE HORD"
scribbled thusly:

The airfoil is there in all cases, in this respect; as the sail aqttacks
the
wind, reguardless of the angle, some air flows on both sides of the sail.
Wind flowing over the most leeward side of the sail creates a partial
vacume
on that side, so with air pressure stronger on one side the sail is
"pushed" or "drawn" to the direction where the low pressure is.
Even with the wind directly astern, a low pressure is created on the
front
of the sail, and the sail(boat) is drawn forward. Hope that is as clear
as
I mean it to be. Welcome to the intoxicaion of sailing.

Dave Hord.



OK, that's Bernoulli.

Now I'd suggest you look into Newtonian explanation of lift
ie deflection.


Oz1...of the 3 twins.

I welcome you to crackerbox palace,We've been expecting you

Hmm, I still have that High school graduation project I did a few years
back. I explained in it how most of that works and a couple other things
with vector format and diagrams. If anyone wants it just email me.

"plugster" wrote in message
nk.net...
It is a simple matter to derive "Bernoulli" using Newtonian equations and
principals. They are the same thing. One common mistake people have with
Bernoulli is using scalar speed and not vector velocity. If you use
scalar
speed, Bernoulli is then only valid in "one" dimensional flow like that
approximated in pipes. Pipe flow observations is what Bernoulli used to
formulate his equations.

Mark

"Capt. Mooron" wrote in message
news:bqKOd.17903$K54.4882@edtnps84...
On Wed, 09 Feb 2005 08:49:14 GMT, "DAVE HORD"
scribbled thusly:

The airfoil is there in all cases, in this respect; as the sail
aqttacks
the
wind, reguardless of the angle, some air flows on both sides of the
sail.
Wind flowing over the most leeward side of the sail creates a partial
vacume
on that side, so with air pressure stronger on one side the sail is
"pushed" or "drawn" to the direction where the low pressure is.
Even with the wind directly astern, a low pressure is created on the
front
of the sail, and the sail(boat) is drawn forward. Hope that is as
clear
as
I mean it to be. Welcome to the intoxicaion of sailing.

Dave Hord.



OK, that's Bernoulli.

Now I'd suggest you look into Newtonian explanation of lift
ie deflection.


Oz1...of the 3 twins.

I welcome you to crackerbox palace,We've been expecting you