(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

On Mon, 22 Nov 2004 04:02:33 GMT, Mac wrote:

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?

I misread your question before my previous answer, which therefore
made no sense. I thought you were asking about the transition between
drawing and stalling. The boom would be to port in either case with
the wind on starboard.

As the wind goes aft, the boom must be let out farther to maintain
flow. The mast is the leading edge.

When the wind is really aft, you would square the sail to the wind,
letting it stall. Then the drag of the sail is pushing the boat.

If you understand this so far, the real question becomes "Is there a
wind angle where the boat will go faster stalled than drawing, even
without the boom or sail hitting the rigging?

That is the question I was answering before, and it is not what you
actually asked.




Rodney Myrvaagnes J36 Gjo/a


Does one child rape really change Strom Thurmond's lifetime record?
For better or worse?

Capt. Neal® writes:

Poor fellow! The man lost his life primarily because
of poor design by the naval architect.

Those C&Cs are a death trap in more than one way it seems.

But, to design a cruising boat with a boom so low that it
can smack you up side the head is criminal. I should think
a nice little lawsuit would straighten out C&C and the
negligent designer.

You won't find a Wm. Tripp Jr. designed cruiser with such
flaws.

CN

R.



Actually, you will.

I have a Columbia 32, designed by none other than William Tripp Jr,
and the boom sweeps over the cockpit definitely below head-height. At
least if I have the 'flattening reef' in the main out (I think there
is a fancier name for it but I forgot it). If I have inexperienced
crew, I sometimes put the flattening reef in even in light airs so
that the boom is a half-foot higher and less dangerous.

--Ernst

Columbia 32 #25 'Tavernier'

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.

Poor fellow! The man lost his life primarily because
of poor design by the naval architect.

Those C&Cs are a death trap in more than one way it seems.

But, to design a cruising boat with a boom so low that it
can smack you up side the head is criminal. I should think
a nice little lawsuit would straighten out C&C and the
negligent designer.

You won't find a Wm. Tripp Jr. designed cruiser with such
flaws.

CN



"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.

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.

Capt Neal says:

Poor fellow! The man lost his life primarily because
of poor design by the naval architect.

Except that he could have been standing on a cockpit seat, or the coachroof. I
would not design a boat 29ft long with a boom more than 6ft above the top of
the coachroof, and I would imagine you wouldn't buy it if it existed somewhere.
6ft above cockpit sole, with a couple of extra inches for the tall folks, is
about it for a boat that size, usually. Plenty of dinghies have booms that
long, and minimal "ducking room"

I'm not trying to excuse C&C here, if they need it, just pointing out that a
fragmented report can be taken awrong.

Steve
Stephen C. Baker - Yacht Designer
http://members.aol.com/SailDesign/pr...cbweb/home.htm

Love the name of your boat. There is a town in the Keys with that name, BTW.

What's your boom doing so low? Check the mast and look for an old, faded-
out black line. This should be where the boom is located. Chances are
somebody lowered the boom and increased the mainsail size. There is no
reason on that 32-footer why the boom is sweeping the cockpit at less
than head height.

To make things safer for yourself either raise the boom to specs or
install a sit-under bimini which makes it impossible for you to get
your head smacked by the boom. You may even have the wrong
mainsail on that boat. Check the specs on the original and measure
yours against it. It could be the leech is longer which some racers
do to lower the end of the boom.

Check out my website for a few pictures of a bimini which is made
to sit under. However, even with the bimini laid down the boom is high
enough not to smack someone upside the head. If you have a boat with
such obvious dangers it is smart to get rid of them one way or the
other before they do you in.

Listen to a man with impeccable credentials and years of experience.

Capt. Neal
USCG Master, Near Shore, 25GT also
Operator Uninspected Passenger Vessels, Near Shore
http://captneal.homestead.com/index.html



wrote in message ...

Capt. Neal® writes:

Poor fellow! The man lost his life primarily because
of poor design by the naval architect.

Those C&Cs are a death trap in more than one way it seems.

But, to design a cruising boat with a boom so low that it
can smack you up side the head is criminal. I should think
a nice little lawsuit would straighten out C&C and the
negligent designer.

You won't find a Wm. Tripp Jr. designed cruiser with such
flaws.

CN

R.



Actually, you will.

I have a Columbia 32, designed by none other than William Tripp Jr,
and the boom sweeps over the cockpit definitely below head-height. At
least if I have the 'flattening reef' in the main out (I think there
is a fancier name for it but I forgot it). If I have inexperienced
crew, I sometimes put the flattening reef in even in light airs so
that the boom is a half-foot higher and less dangerous.

--Ernst

Columbia 32 #25 'Tavernier'

"Capt. Neal®" wrote in message
...
Love the name of your boat. There is a town in the Keys with that name,
BTW.

What's your boom doing so low? Check the mast and look for an old, faded-
out black line. This should be where the boom is located. Chances are
somebody lowered the boom and increased the mainsail size. There is no
reason on that 32-footer why the boom is sweeping the cockpit at less
than head height.


I thought you had walked the plank somewhere!
Anyway, the Mirage 33 I crewed on for 4 years had a boom that was about 6'
1" off the cockpit sole. When I got hit, it was because I was standing on
the seat trying to stow away excess halyard line and I made the mistake of
letting the skipper control the ship's wheel.

On Mon, 22 Nov 2004 14:56:43 -0500, Capt. Neal®
wrote:

Poor fellow! The man lost his life primarily because
of poor design by the naval architect.

Actually, probably poor instruction from the skipper, but it was rough
enough that he might simply have been "thrown upright" to catch his
balance and got clipped. I don't know the fine details, only that he
got "boomed" on both sides of his head, with the second one basically
mushing his brain.

Those C&Cs are a death trap in more than one way it seems.

I own a C&C design and I find them quite safe. I will cop to the
crappy cored decks, however...but they can be remedied.

But, to design a cruising boat with a boom so low that it
can smack you up side the head is criminal. I should think
a nice little lawsuit would straighten out C&C and the
negligent designer.
Too late. Company was sold 15 years ago although the trademark
lingers.

You won't find a Wm. Tripp Jr. designed cruiser with such
flaws.

If you say so...

R.