Propeller Questions

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  • January 23, 2013 10:02 AM
    Reply # 1186992 on 1096423
    Hi Tyler,

    Its an interesting discussion and I don't think you need worry about "opening a can of worms" :)

  • January 23, 2013 10:26 AM
    Reply # 1187028 on 1096423

           Ok I am a cranky old fart that tends to blurt things out. The 2 blade prop cannot perform as well as a 3 blade because for every revolution that it turns there will be 2 times that the blades are behind the keel and not getting a bite. The three blade will always have at least 2 blades in the flow of water getting a bite. This makes the 2 blade better for sailing if you have your shaft marked so you can lock it behind the keel.      No slander intended.


  • January 23, 2013 11:42 AM
    Reply # 1187105 on 1096423
    Deleted user
    Way to go Lee!  I sometimes think we need opinions expressed here a little more firmly. That doesn't mean rudely, which you were not, just more expressive to drive the point home. More than a few times I've seen things posted that really needed a lot more discussion and no one respond, myself included.

    Years ago when selecting a prop I did the research including reading the Propeller Handbook.  I came to the conclusion that while the math and engineering were correct, it really was just a starting point and needed to be tested in the real world.  It's like hull speed, it's real close but a lot of variables can come into play.  I think Lee is right that if a two bladed prop were better overall, more people would be using them.  

    On the other hand, if you're concerned about sailing more then motoring, the two blade might be a better choice.  I think either choice would work for most Westsailors.  While I found Campbell props to be interesting, I felt the Max prop to be a far better choice.  We have three blades for good forward motion, better backing as the blades reverse themselves and lastly the feathering prop reduces drag noticeably.

    We saw a marked improvement in boat boat performance, maybe as much as a half knot at lower wind speeds.


  • January 24, 2013 6:26 AM
    Reply # 1187734 on 1096423
    Anonymous member (Administrator)
    Maybe the next rondy  - we can do side by side testing?  With just the Nor Cal rondy regulars I can think of at least 4-5 prop combinations.. then there is the faired verses unfaired hulls.  
  • February 15, 2014 2:48 PM
    Reply # 1498878 on 1096423
    Deleted user
    A 2 blade prop seems interesting but I have a question about aligning the  blades when under sail.  Is it necessary to go into the engine compartment and align the blades after each use of the engine in order to position the blades behind the keel and out of the flow of water?  Or do the blades move out of the way by themselves from the pressure of the water?
  • February 16, 2014 4:35 AM
    Reply # 1499051 on 1096423
    Deleted user
    The blades do not align on their own! =  freewheeling they will spin and give max drag.

    I have a mark on my shaft coupling, so I can align the prop to the hull and then put it in gear = no rotation +/-

    This I only do when it is worth it (sailing for more than a couple of hours) else I just leave it where it stopped.

    Hope this helps

    P.S. I do have a easy to remove hatch to do this.

  • February 16, 2014 9:01 PM
    Reply # 1499429 on 1096423
    Deleted user

    Thanks for the clarification.  Your response is what I sort of expected.  Before I get a two blade prop I will need to figure out an easy way to align the prop.

    W/32 Quimera
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