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Thread: Best to put off-center prop on Port or Starb side of keel?

  1. #1
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    Default Best to put off-center prop on Port or Starb side of keel?

    I'm thinking about mounting a pod motor on Tempo. It will be beside the keel and hopefully the prop tips, won't extend much below the keel.

    Assuming it's a right-hand screw, which side is preferred?

    Thanks, Mack
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  2. #2
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    Default Re: Best to put off-center prop on Port or Starb side of keel?

    Starboard has the upper blade wash carrying junk away from the hull, albeit perhaps dredging up the bottom. If the boat's shape is normal, moving the unit aft might give room to get the prop tips out of the mud.

  3. #3
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    Default Re: Best to put off-center prop on Port or Starb side of keel?

    Assuming steering with tiller and discounting the pod's ability to rotate and deliver directional thrust...

    In forward, your RH prop will want to push the stern to starboard...except much of the lateral thrust will / may be blocked by the keel if pod is installed to starboard.
    In reverse the RH prop will tend to kick the stern to port...except much the lateral thrust will be / may be blocked by the keel if pod is installed to port.

    Personally, I would install it to starboard to maximize my thrust and maneuverability in reverse.

    Prop kick is your friend once you know its direction and force.

    Kevin
    There are two kinds of boaters: those who have run aground, and those who lie about it.

  4. #4
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    Default Re: Best to put off-center prop on Port or Starb side of keel?

    What design is your Tempo?
    “Eventually, all things merge into one, and a river runs through it. The river was cut by the world's great flood and runs over rocks from the basement of time. On some of those rocks are timeless raindrops. Under the rocks are the words, and some of the words are theirs."

  5. #5
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    Default Re: Best to put off-center prop on Port or Starb side of keel?

    You don’t get lateral thrust, in the ordinary sense of the word, with a side mounted prop. You get something different.

    I had one for 29 years and I know. She had a big LH wheel to port. Attempts to berth port side to, in the time honoured way, were fine until the untutored helmsman went astern to stop her and kick the stern in, as per textbook. She would immediately jump six feet sideways off the berth. Did it every time!

    On the other hand, whilst turning away from the prop was a lottery, turning towards the prop with the rudder hard over was impressive!

    You will get slightly better ahead performance if you mount the wheel as Ian suggests.
    Last edited by Andrew Craig-Bennett; 09-16-2021 at 04:11 PM.
    IMAGINES VEL NON FUERINT

  6. #6
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    Default Re: Best to put off-center prop on Port or Starb side of keel?

    I crewed on a NY32 with off center prop...backing was a byotch. Forward ok.

  7. #7
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    Default Re: Best to put off-center prop on Port or Starb side of keel?

    Quote Originally Posted by rbgarr View Post
    What design is your Tempo?
    I built Tempo from Reuel Parker's The Sharpie Book. (A book I highly recommend regardless if you're building a sharpie or not.)


    18-foot Modified Sharpie Skiff, Hooper Island, Chesapeake Bay, 1906.

    "The type represents the highest stage of evolution of the sharpie into the deadrise skiff. The model is moderate, neither a burdensome workboat nor a flat out racer."

    mockup glued 2 - 1.jpg

    mockup glued 2 - 1 (4).jpg

    I don't think there will be much prop walk on this Crab Skiff. Reverse will probably cavitate and a folding 2 blade prop won't help back-down.
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    When we remember we are all mad, the mysteries disappear and life stands explained.

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  8. #8
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    Default Re: Best to put off-center prop on Port or Starb side of keel?

    Quote Originally Posted by leaotis View Post
    18-foot Modified Sharpie Skiff, Hooper Island, Chesapeake Bay, 1906.

    "The type represents the highest stage of evolution of the sharpie into the deadrise skiff. The model is moderate, neither a burdensome workboat nor a flat out racer."

    mockup glued 2 - 1.jpg


    I don't think there will be much prop walk on this Crab Skiff. Reverse will probably cavitate and a folding 2 blade prop won't help back-down.
    I'm wondering if the pod/prop would fit into a cutout in the rudder..


    It's just a thought.
    I'd much rather lay in my bunk all freakin day lookin at Youtube videos .

  9. #9
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    Default Re: Best to put off-center prop on Port or Starb side of keel?

    Quote Originally Posted by leaotis View Post
    I built Tempo from Reuel Parker's The Sharpie Book. (A book I highly recommend regardless if you're building a sharpie or not.)


    18-foot Modified Sharpie Skiff, Hooper Island, Chesapeake Bay, 1906.

    "The type represents the highest stage of evolution of the sharpie into the deadrise skiff. The model is moderate, neither a burdensome workboat nor a flat out racer."

    mockup glued 2 - 1.jpg

    mockup glued 2 - 1 (4).jpg

    I don't think there will be much prop walk on this Crab Skiff. Reverse will probably cavitate and a folding 2 blade prop won't help back-down.
    That is sweet! Any more images of the boat floating around the forum?
    If you ever feel the mood come over you to post more pics I'd be grateful.
    ​​♦ During times of universal deceit, telling the truth becomes a revolutionary act
    ♦ The further a society drifts from truth the more it will hate those who speak it
    ♦ If liberty means anything at all, it means the right to tell people what they do not want to hear
    ♦ George Orwell

  10. #10
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    Default Re: Best to put off-center prop on Port or Starb side of keel?

    Quote Originally Posted by Autonomous View Post
    That is sweet! Any more images of the boat floating around the forum?
    If you ever feel the mood come over you to post more pics I'd be grateful.
    Thanks for asking Auto.

    Tempo, Mack, Golden Beach - 1.jpg
    This is my favorite.

    Tempo being built.

    Tempo videos
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    When we remember we are all mad, the mysteries disappear and life stands explained.

    Mark Twain

  11. #11
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    Default Re: Best to put off-center prop on Port or Starb side of keel?

    Or hang the pod on the rudder with the prop as close to on center and the blades as near the back of the rudder as makes any sense.

    As you take the ground on a falling tide put the helm down so the prop and most of the rudder stay clear.

  12. #12
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    Default Re: Best to put off-center prop on Port or Starb side of keel?

    Or make a cutout in the rudder that holds the pod. Fair all nicely.

  13. #13
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    Default Re: Best to put off-center prop on Port or Starb side of keel?

    Thanks leaotis! The no-nonsense bow and sweeping sheer evoke a very yar impression.
    ​​♦ During times of universal deceit, telling the truth becomes a revolutionary act
    ♦ The further a society drifts from truth the more it will hate those who speak it
    ♦ If liberty means anything at all, it means the right to tell people what they do not want to hear
    ♦ George Orwell

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