Rudder not centred???

Discussion in 'Boat Design' started by Paul R, Feb 10, 2010.

  1. Paul R
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    Paul R New Member

    Looking to find an answer to what are the effect(s) on a vessel if a single rudder located on the stern is off centre from the hull?
     
  2. messabout
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    messabout Senior Member

    Are you referring to a sailboat or a single screw power boat?
     
  3. Paul R
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    Paul R New Member

    Sail boat.
     
  4. El Sea
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    El Sea Junior Member

    Props are generally off-center so as to remove the prop shaft with out dropping the rudder.... Only a slight and most of the time un-notice effect on steering.
     
  5. lewisboats
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    lewisboats Obsessed Member

    Depending on how far off center it is the effects can be negligible to serious. If it is only a couple inches off centerline it shouldn't make all that much difference but if it is way off to the side it just may come out of the water enough to affect steering when heeled. Some boats have twin rudders...when heeled one is always buried well so as to provide steering.
     
  6. alan white
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    alan white Senior Member

    When the boat heels the rudder can on the one hand rise out of the water, losing bite. On the other hand it will increase area on the other tack, and there may be helm balancing issues as a result.
    As long as rudder is nearly centered, this shouldn't be a problem.
     
  7. TollyWally
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    TollyWally Senior Member

    In the past sometimes either the shaft and wheel or the rudder was slightly offcenter to optimise effective thrust and negate the need for the rudder to be slightly cocked when moving forward. William Atkin was fond of this little trick. It isn't much but optimization is often the sum of many small things rather than just a few large ones.
     
  8. philSweet
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    philSweet Senior Member

    I presume there is a reason you are considering this. Are you trying to shift a kicker more to the center? Clear a tiller of an obstruction? Center your butt on the stern deck? What is the size, weight, and type of sailboat? Is this a transom hung rudder?
     
  9. Paul R
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    Paul R New Member

    Thanks for the feedback!
    I was curious wether there would be effect on the stability when underway and if there would be any sufficient drag/loss in speed encountered when steering. The rudder is off centre due to a manufacturing fault, although not by much, so I believe the question have been answered.
     
  10. Easy Rider
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    Easy Rider Senior Member

    Just for theoretical fun.
    What if the rudder was off center enough to be outside the propwash and located on the correct side to counteract the directional effects of prop walk, or as some people put it ..P factor. If the boat had a CCW propeller and the rudder off to port .. could neutralize everything and be very efficient. Ha Ha

    Easy
     
  11. rasorinc
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    rasorinc Senior Member

  12. TollyWally
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    TollyWally Senior Member

    hmmm see post 7
     

  13. rasorinc
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    rasorinc Senior Member

    Missed that totally--you explaned it well as the plan info does not go into it.
     
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