Power Rudder is Unique to Duffy Boats

Discussion in 'Electric Propulsion' started by OCB, Jun 20, 2018.

  1. OCB
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    OCB Junior Member

    Seen the 18" boat driving down the road on the way to the local ramp. I stop and talk to the Capain that said he was easy to drive. Duffy has made some big claims.
    – 100% Steering Control in Reverse

    – 35% More Efficient Thrust

    – Superior Maneuverability (boat turns in its own length!)

    – Patented 4-Blade Weedless Prop

    – Whisper Quiet Operation

    – Compact Design Creates Luxurious Interior Space

    – Trusted Duffy Reliability (Over 10 years to develop)

    – No Belts, No Adjusters, and No alignment concerns!


    Power Rudder | Duffy Electric Boat Company https://duffyboats.com/power-rudder/
     
  2. kerosene
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    kerosene Senior Member

    35% more and superior... to what?
    Older model?
     
  3. OCB
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    OCB Junior Member

    35% more efficient then the belt drive design.

    When compared to standard inboard design, it has superior steering in reverse IMO.

    OCB
     

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  4. gonzo
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    gonzo Senior Member

    WOW, they built a sterndrive
     
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  5. OCB
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    OCB Junior Member

    Thank you for the input. you're very sharp!

    "Edit" for poor spelling. Sometimes I'm not to sharp.
     
    Last edited: Jul 21, 2018
  6. BlueBell
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    BlueBell Ahhhhh...

    I've never seen a boat driving down the road before accept for an amphibious one.
    And are you sure it was only 18"?
    That's pretty small.

    "Your very sharp!"
    It's "you're" not "your".

    I drove a Duffy 20 commercially for a summer.
    They are all the things OCB claims they are but the "live rudders" wear out quickly.
    They are proprietary and very expensive.
    Where I worked was overhauling theirs on their own.
    They had four in operation about six hours a day, 7 days a week, four months a year.
    16, deep-cycle, lead acid, golf cart batteries would last about 6 - 8 hours at wide open throttle.
    But there was a 4 knot speed limit, so at 3/4 throttle they lasted all day no problem.
    Dockside maneuverability was impressive.

    Duffy voided the warranty as they were never designed for commercial use.
    Other than the live rudder wear, they were great boats.

    Oh, and the live rudder is not unique to Duffy, some of our ferries use them too.
     
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  7. OCB
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    OCB Junior Member


    Thank you very much, BlueBell for the real hands on input with the Duffy live rudder drive. Yes that was a 18' Duffy. It's very hard to debate design without getting real world input. Live rudder is a good design IMO and I have been working on new design for some time now. I will have no gears in the lower unit.
    I was thinking the ring gear was very small for the size boat and motor. Were the gears in the Live rudder the weak point?
    When I talk to people at Duffy and the boat owners I get the different story from them.

    OCB
     
  8. BlueBell
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    BlueBell Ahhhhh...

    You are most welcome OCB.
    I can't remember if it was the gears specifically but it required purchasing a new, $5000 rudder!
    Likely gears, bearings, seals, shaft wear.
    Ask Duffy specifically regarding commercial use on southern Vancouver Island if you're chatting with them.
    Four boats, heavy use.
    As you can tell, I don't want to name names, it's a small town.

    Building the motor into the rudder would be the way to go but the motor was the size of a large coffee can, 6HP.
    If you are designing to build, I'd go with the motor in a rotating pod and forget the rudder.
    I drove electric gondolas for a summer that had commercial electric pods that rotated 360*.
    One forward and one aft with remote control.
    They were maneuverable.
    Cheers
     
  9. BlueBell
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    BlueBell Ahhhhh...

    So, what did Duffy have to say?

    How's your design coming?
     
    Last edited: Jul 26, 2018
  10. OCB
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    OCB Junior Member


    I have not contacted Duffy yet. Trying to finish my prototype before calling them out on drive design.
    I have been doing R&D all week.
    I had to do some other R&D work on drive lines.

    I'm currently working on cad drawing for the 360* design with and without no rudder. After testing a sail drive is next.



    We are testing my drive design is around @ 200 ( ft lbf ) or 271.16 ( n-m ) 3/4" shaft. 2 1/4" O.D.

    I will use the Duffy prop for testing .


    OCB







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  11. gonzo
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    gonzo Senior Member

    What are the advantages over an outboard?
     
  12. BlueBell
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    BlueBell Ahhhhh...

    The rudder swings 180 degrees plus.
     
  13. gonzo
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    gonzo Senior Member

    That is the same that Z drives do,., which are basically an outboard without turning stops.
     
  14. OCB
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    OCB Junior Member

    Not if you have inboard motor with horizontal shaft driven. I have posted before about the rudder propeller like the Duffy design in the past. Outboards and Z drives both have down falls compared to inboards. Every design has down falls. The outboard upfront cost is way they are selling best. I don't see to many big boats with outboards or Z drives where I live. Do you have any input for this type Rudder, drive or propeller I posted Gonzo?

    OCB
     

  15. gonzo
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    gonzo Senior Member

    Yes, It combines the bad points of an inboard and an outboard or z-drive. The engine is in an enclosed compartment which makes it difficult and expensive to service, plus it takes interior room and may put fumes and oil into the living quarters. It also has an exposed propeller that is more likely to get damaged.
     
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