Oops! Thanks for the correction Leslie. Being an EE, not a ME or fluids guy
I should be more careful.
I worked at APL and our auditorium is named after a not so famous scientist.
Don Wagner
C&C 41 CB
Der Baron
-----Original Message-----
From: Leslie Paal via CnC-List
Sent: Sunday, August 02, 2015 1:17 PM
To: cnc-list@cnc-list.com
Cc: Leslie Paal
Subject: Re: Stus-List Howling rigging
https://en.wikipedia.org/wiki/Theodore_von_K%C3%A1rm%C3%A1n
von Karman was Hungarian. I spent many hours in an auditorium named after
him at JPL.
Leslie.
--------------------------------------------
On Sat, 8/1/15, Don Wagner via CnC-List <cnc-list@cnc-list.com> wrote:
Subject: Re: Stus-List Howling rigging
To: cnc-list@cnc-list.com
Cc: "Don Wagner" <don.wag...@verizon.net>
Date: Saturday, August 1, 2015, 6:40 AM
The vibrations and the singing noises that you have
observed are
classical examples of vortex shedding. They were
originally described by a
German fluid dynamics engineer, Theodore von Karmann.
If you are interested, do a search on “vortex
shedding”. Wikipeda has a
good description of the phenomena with some pix. You might
also search “
von Karmann vortex street”
I’ve experienced it in my rigging, and occasionally
from my centerboard at
certain wind speeds or boat speeds
Don Wagner
C&C 41 CB
Der Baron
From: Joel Aronson
via CnC-List
Sent: Saturday, August 01, 2015 2:39 AM
To: cnc-list@cnc-list.com
Cc: Joel
Aronson
Subject: Re: Stus-List Howling
rigging
Had
a similar hum while coming back from Newport. The engineer
on board put a
clothes pin on the shroud to change the harmonics. Worked
for several
hours.
Joel
On Saturday,
August 1, 2015, Russ & Melody via CnC-List
<cnc-list@cnc-list.com>
wrote:
Don't listen to him, Jim. I
can tell he's just making things
up. The name was Peat and we don't have pints of
rum... maybe a litre or two.
And to settle the ghost,
try hoisting a fender alongside the mast
about half way up. You will be amazed how it can settle
the rig if you have
oscillation. I had to do just that at the Boho Bash, 4
weeks ago.
Go
ogle vortex breaker.
Cheers, Russ
Sweet 35 mk-1
At
09:56 PM 31/07/2015, you wrote:
Dennis, where the hell did you
come up with
that?
Jim Watts
Paradigm Shift
C&C 35 Mk
III
Victoria,
BC
On 31 July 2015 at
21:04, Dennis C. via CnC-List
<javascript:_e(%7B%7D,'cvml','cnc-list@cnc-list.com');>
wrote:
It's the ghost of Penelakut Pete. He
drowned in Clam Bay when
he fell overboard after consuming a few pints of
rum. Legend says
he only comes out on breezy nights.
Dennis C.
Touche' 35-1 #83
Mandeville, LA
On Fri, Jul 31, 2015 at 9:26 PM, Jim Watts
via CnC-List <javascript:_e(%7B%7D,'cvml','cnc-list@cnc-list.com');>
wrote:
On our latest trip north, we anchored in Clam
Bay and had a strange
problem. At a certain wind speed, the shrouds would
start to hum,
sometimes making the boat shake with vibration. The
major vibration was
felt in the small rod running to the underside of
the upper spreaders
and in the mast and backstay. I backed each
shroud one off half a
turn and it really didn't do much except make
those shrouds look loose
to me, but I'm sure I can't tell the
difference of 1/128th of an inch.
It eventually faded as the wind dropped.
For the next ten days, in all sorts of
conditions, we didn't hear
it, but when we anchored in the same bay 10 days
later, we got it again.
Any explanation except witchcraft?
Â
Jim Watts
Paradigm Shift
C&C 35 Mk III
Victoria, BC
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