[Rhodes22-list] Effect Of Canting The Rudder Blade Forward?
Roger Pihlaja
rhodes22-list@rhodes22.org
Tue, 27 Aug 2002 11:53:36 -0400
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For the size boat it is, the Rhodes 22 has a huge rudder. With the =
rudder hung off the transom, the forces developed by the rudder blade =
also operate thru a lever arm of several feet. The net result of these =
two factors is that the balance of the helm is very sensitive to the =
position of the kick-up rudder blade. On Dynamic Equilibrium, having =
the rudder blade kick up even 10 deg causes a significant amount of lee =
helm.
The rudder head on Dynamic Equilibrium has a solid mechanical stop which =
limits the forward travel of the rudder blade. On my boat, the rudder =
blade travel stops at the point where the leading edge of the rudder =
blade is vertical. On your boat, if someone cludged together a rudder =
head assembly wherein the rudder blade is allowed to swing forward past =
vertical; then, I would expect you would experience weather helm with =
the rudder blade pivoted all the way forward past vertical.
With a cludged up rudder assembly, It may also be possible that the =
gudgeons & pintles on your boat are incorrect, which may have placed the =
rudder blade too far forward or too far aft or at the incorrect =
immersion depth. You really need to have a long talk with Stan @ GBI. =
This is one of those instances where you might want to consider =
purchasing the entire replacement rudder assembly including the gudgeons =
& pintles from GBI. Getting the rudder blade geometry correct is pretty =
critical & +/- fractions of an inch or +/- a few degrees are significant =
errors in this case.
Roger Pihlaja
S/V Dynamic Equilibrium =20
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<DIV><FONT face=3DArial size=3D2>For the size boat it is, the Rhodes 22 =
has a huge=20
rudder. With the rudder hung off the transom, the forces developed =
by the=20
rudder blade also operate thru a lever arm of several feet. The =
net result=20
of these two factors is that the balance of the helm is very sensitive =
to the=20
position of the kick-up rudder blade. On Dynamic Equilibrium, =
having the=20
rudder blade kick up even 10 deg causes a significant amount of lee =
helm.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>The rudder head on Dynamic Equilibrium =
has a solid=20
mechanical stop which limits the forward travel of the rudder =
blade. On my=20
boat, the rudder blade travel stops at the point where the leading edge =
of the=20
rudder blade is vertical. On your boat, if someone cludged =
together a=20
rudder head assembly wherein the rudder blade is allowed to swing =
forward past=20
vertical; then, I would expect you would experience weather helm with =
the rudder=20
blade pivoted all the way forward past vertical.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>With a cludged up rudder assembly, It =
may also be=20
possible that the gudgeons & pintles on your boat are =
incorrect, which=20
may have placed the rudder blade too far forward or too far aft or at =
the=20
incorrect immersion depth. You really need to have a long talk =
with Stan @=20
GBI. This is one of those instances where you might want to =
consider=20
purchasing the entire replacement rudder assembly including the gudgeons =
&=20
pintles from GBI. Getting the rudder blade geometry correct is =
pretty=20
critical & +/- fractions of an inch or +/- a few degrees are=20
significant errors in this case.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Roger Pihlaja</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>S/V Dynamic Equilibrium =20
</FONT></DIV></BODY></HTML>
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