Propeller Questions

  • January 18, 2013 12:13 PM
    Reply # 1183188 on 1096423
    The 3 blade will be better in forward and reverse IMHO...you are trading some responsiveness in forward and reverse for less drag when sailing. 
  • January 22, 2013 6:42 AM
    Reply # 1185834 on 1096423
    Deleted user
    Just from my experience .  I have a 1:1 transmission and switched over to a 14" 7 sailor prop over a 3 blade mouse ear michigan 13.5" 6 and found the sailor does a better job under motor, so for me the old thought of the three is better than 2 did not prove correct.
  • January 22, 2013 9:13 AM
    Reply # 1185938 on 1096423
    Norm, are you saying the 2 blade Campbell Sailer prop gave you better motoring performance over a 3 blade "conventional" Michigan Wheel prop?
  • January 22, 2013 10:57 AM
    Reply # 1186042 on 1096423

    Gary,

    Norm is right.  Propeller theory states that 1 blade is the best (like a sculling oar), but we have yet to figure out the balance and vibration issues that come along with it.  3 blades create more of a "stirring" (wasted energy) than propulsion/thrust, hence a 2 blade performs more efficiently.  We are also constrained by the physical space.  A 3 blade can be smaller and perform, but it comes at a cost with drag and lower efficiency.  It is always a compromise. 

    Tyler

  • January 22, 2013 2:44 PM
    Reply # 1186226 on 1096423
    Very interesting!
  • January 22, 2013 5:36 PM
    Reply # 1186328 on 1096423

          Oh horse poop! If this were true every fisherman in my harbor with a displacement style full keel boat would be running a 2 blade instead of the 3 or 4 blade they are running.Sometimes a little common sense goes a long way. I run a campbell 3 blade and have tried a w32 with a two blade. The 2 blade has the advantage under sail but not motoring.

                                                                            Lee

  • January 23, 2013 5:42 AM
    Reply # 1186715 on 1096423

    Lee,

    It's not horse poo, it's a paradigm shift towards a different alternative that better suites individual sailing preferences, like Norm's or mine. 

    TJB

  • January 23, 2013 6:06 AM
    Reply # 1186726 on 1096423
    Anonymous member (Administrator)
    Life is short folks -- let's be gentle on one another -- differences of opinion are just fine -- labeling an opinion/person are not so fine - you are allowed to edit posts after you have Posted if needed.



    Jay 
  • January 23, 2013 6:28 AM
    Reply # 1186743 on 1096423
    :)

    I have to say I agree with Lee :) The 3 blade will have more thrust..if it is replacing a prop of the same diameter and style. Of course if you replace a 12" 3 blade with a 17" 2 blade, the boat might motor better. Its all relative.

    Jay, I don't think anyone is getting too worried...we're all adults here :)
    Last modified: January 23, 2013 6:28 AM | Anonymous member
  • January 23, 2013 7:24 AM
    Reply # 1186822 on 1096423

    Gary: you are correct as well.  Not changing the diameter and pitch of the prop, would advocate a 3 blade provide more thrust, but at a lower efficiency of energy transfer.  Again it is a trade off, and I'll will leave it as that.

    As I originally posted, I was hoping not to open a can of worms.  I got the feedback originally desired, and thanks to those whom contributed on all sides of the argument.

    TJB

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