Posted by mainewonder2000 (proberts@…>)
Yesterday we had our first sail in Outrun ex Scoter. It was great a
beautiful day and everything worked well. My question, this is our
second f F-21 the first being a shoal draft that was years ago and it
had the same vibration when going very fast. We came to enjoy it as
it meant we were doing a good job. However with outrun who does
not have a knotmeter but is the fin keel version we use a GPS to tell
the knots. On the wind we saw up to 7.2 with no vibration. as soon as
we started reaching the Gps dropped to 6.2 but the vibration started.
Realizing the GPS is speed over the bottom not through the water due
to tide etc I believe we were faster hence the vibration. Anyone
else expierence the same vibration ? And Ideas as to just what it is
?
Also she came with a new mainsail upon trying to fit it we found it
is for a F-20 not a F-21 so it is too small to be of any use. anyone
need a F-20 mainsail in brand new condition reasonable ?
Posted by Medium Al (hjulbyhavn@…>)
My F21-S has that same vibration but I don’t belive that it is
proportional to speed although it happens at high speed. Rather it is
undoubtedly a resonance of sorts due to interaction between flow
turbulence and hull flexibility. Technically any vibration is a waste
of energy so its absense at some points of sail is probably a good thing.
What size is a F20 sail anyway?
Posted by mainewonder2000 (proberts@…>)
What size is a F20 sail anyway?
I have not measured it but when we tried to put it on our 21 it was
at least a foot too short in all dimentions, would you like me to
measure it ? I agree about the vibration but it is hard to believe
the hull is flexing as strong as it is. I am trying to connect it to
turbulence between keel and rudder that is why I was suprised the fin
keel had the same vibration as the shoad draft .
Posted by Charlie L. (clivaday@…>)
I’ve had many different boats “shudder”, usually on reaches, with the
sails well trimmed, and good hull speed. Most sailors consider this a
good sign of proper sail trim. Could be the leading/trailing edge of
the rudder, when there is no weather/lee helm?
— In freedomyachts2003@yahoogroups.com, “mainewonder2000”
<proberts@p…> wrote:
What size is a F20 sail anyway?
I have not measured it but when we tried to put it on our 21 it was
at least a foot too short in all dimentions, would you like me to
measure it ? I agree about the vibration but it is hard to
believe
the hull is flexing as strong as it is. I am trying to connect it
to
turbulence between keel and rudder that is why I was suprised the
fin
keel had the same vibration as the shoad draft .
Posted by Bill Fischer (billllll@…>)
I have a shoal draft F21, this shudder has only happened a few times. It is a great feeling because you are always at MAX speed.
----- Original Message -----
From: Charlie L.
To: freedomyachts2003@yahoogroups.com
Sent: Tuesday, June 14, 2005 10:34 AM
Subject: [freedomyachts2003] Re: F-21 vibration
I’ve had many different boats “shudder”, usually on reaches, with the sails well trimmed, and good hull speed. Most sailors consider this a good sign of proper sail trim. Could be the leading/trailing edge of the rudder, when there is no weather/lee helm? — In freedomyachts2003@yahoogroups.com, “mainewonder2000” <proberts@p…> wrote:> > > > What size is a F20 sail anyway?> > I have not measured it but when we tried to put it on our 21 it was> at least a foot too short in all dimentions, would you like me to> measure it ? I agree about the vibration but it is hard tobelieve> the hull is flexing as strong as it is. I am trying to connect itto> turbulence between keel and rudder that is why I was suprised thefin> keel had the same vibration as the shoad draft .
Posted by Brian Guptil (sailordude@…>)
Gentlemen;
Humm is a good
thing.
I beg to differ
and suggest that the humming is actually robbing you of speed. It is most
likely an oscillation somewhere in the undercarriage like keel or rudder.
If it is the rudder due to bad bearings that is really bad, but my experience
with high speed catamarans is that it is turbulence off of the trailing edge.
The fix for the Hobies is to sand and fair the trailing, and to a lesser
degree, the leading edge of the foils.
Brian
Guptil sailordude@…
-----Original Message-----
From: freedomyachts2003@yahoogroups.com [mailto:freedomyachts2003@yahoogroups.com] On Behalf Of Bill Fischer
Sent: Tuesday, June 14, 2005 11:41 AM
To: freedomyachts2003@yahoogroups.com
Subject: Re: [freedomyachts2003]
Re: F-21 vibration
I have a shoal draft F21, this
shudder has only happened a few times. It is a great feeling because you
are always at MAX speed.
----- Original Message -----
From: Charlie L.
To: freedomyachts2003@yahoogroups.com
Sent: Tuesday,
June 14, 2005 10:34 AM
Subject:
[freedomyachts2003] Re: F-21 vibration
\
I’ve had many different boats “shudder”,
usually on reaches, with the
sails well trimmed, and good hull speed. Most
sailors consider this a
good sign of proper sail trim. Could be the
leading/trailing edge of
the rudder, when there is no weather/lee helm?
— In freedomyachts2003@yahoogroups.com,
“mainewonder2000”
<proberts@p…>
wrote:
What size is a F20 sail anyway?
I have not measured it but when we tried
to put it on our 21 it was
at least a foot too short in all dimentions,
would you like me to
measure it ? I agree about the
vibration but it is hard to
believe
the hull is flexing as strong as it is.
I am trying to connect it
to
turbulence between keel and rudder that is
why I was suprised the
fin
keel had the same vibration as the shoad
draft .
\