Question on Propeller Rotation and Effects of Outboard Motor on Direction of Boat

Discussion in 'Capri/Catalina 14 Talk' started by jdtaillant, Aug 3, 2008.

  1. jdtaillant

    jdtaillant New Member

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    Here's a techie question for the physisist sailors: I understand that propellers, depending on how they rotate, will pull the boat Starboard or Portside. I don't recall which is which? So that leads to the question, given than the Outboard motor mount is on the Port Side, which would suggest to me that mounting a motor on Portside would pull the boat towards Starboard, should one hence choose a propeller that rotates so that the boat pulls Portside to cancel out effects??? Am I making sense or does it really not matter?
     
  2. Solarfry

    Solarfry Member

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    Prop Walk

    You cannot change propeller to other direction. It will make boat go backwards. Prop Torque induced Prop Walk is a fact of life with outboards.

    Ya gotta learn to live witit.:D
     
  3. jdtaillant

    jdtaillant New Member

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    Propeller Directions

    I understand the forward/reverse difference.
    But, alas, here's what I picked up in Sailing Class (mind you I only just graduated!):

    (Sorry the lingo comes from spanish so I may have the translation wrong)

    Seen from the stern and IN BOTH cases in FORWARD march,

    Dextrogiras Propellers rotate CLOCKWISE (the typical type or right handed propellers)
    Levogiras Propellers rotate COUNTERCLOCKWISE (Counterrotation or lef handed)

    My notes indicate that Dextrogiras Propellers tend to push the bow Starboard (to the right), while Levogiras Propellers tend to push the bow Portside (to the left).

    Hence, my original question, given that the motor mount on the Capri 14.2 is Portside, which if the propeller were indifferent would to my logic push the bow towards Starboard (to the right), should you not hence prefer a propeller that tends to Portside (the LEVOGIRAS type, or left handed) to cancel out the pull????

    It seems from the research that my intuition and theory are correct, HOWEVER, I am not sure that when it comes to size and scale of a Capri 14.2, that it really makes any difference at all. It may not, and that is my real question!


    some litterature I have found:
    http://www.boatfix.com/how/props.html
    http://en.wikipedia.org/wiki/Propeller#Marine
     
  4. Drewber

    Drewber New Member

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    motor out if you must, point into the wind and put the sails up and shut down the motor.
     

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