"Randy Haupton" wrote in message
...
I get a vibration in the steering system of my old Owens 27. I've checked
and had checked all the steering linkages and the gearbox and there is no
play. Also I checked the boat (it is old) for hogging underway and none
what so ever. I've got the problem down to being that the rudder is not
balanced. I have called dozens of prop shops up and down the coast to see
if they do rudder balancing, none of them do. I can't even get them to
point to someone who does. Does anyone know of any shops that balance
rudders? Otherwise, it looks like I'm going to have to braze material on to
the leading edge of the rudder and grind it off in a trial and error
fashion until the rudder balance. One old guy said to try bending the
rudder relative to the shaft so the center of effort is moved forward but I
don't think this is good advice. It would give the rudder a forward canted
leading edge which I don't think is good. Thanks.

Randy


You might be experiencing prop-whirl-flutter. Have you changed the prop
recently? If you went from a 3 blade to a 4 blade you could see this type of
problem. Does the vibration get worse on a port or starboard turn?

Ron

On 2008-02-18 17:53:58 -0500, "Ron Fiengold" said:

"Randy Haupton" wrote in message
...
I get a vibration in the steering system of my old Owens 27. I've
checked and had checked all the steering linkages and the gearbox and
there is no play.

You might be experiencing prop-whirl-flutter. Have you changed the prop
recently? If you went from a 3 blade to a 4 blade you could see this
type of problem. Does the vibration get worse on a port or starboard
turn?

I'm thinking this may be closer to the situation. I built a balanced
rudder (NACA 0012 http://homepage.mac.com/jerelull/FileSharing.html)
and at certain speeds and heels, we get a slight flutter that seems to
be from water disturbed by the prop and/or keel. Since we're
transom-hung and have a tiller, there's no where else it could come
from.

--
Jere Lull
Tanzer 28 #4 out of Tolchester, MD
Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/

Oooooops, He has an Owens 27 .... a stinkpot.

Vibrations in high speed props can arise from various causes: bent
prop, prop out of balance, shaft-whip due to engine misalignment, bent
propshaft, missing or severely worn cutless bearing, etc. etc.
A flat-plate rudder on a powerboat 'can' develop vibrations
(excitation of natural frequency) but that is extremely rare on a
powerboat so check the above first, starting with the engine
alignment.