Electric propulsion for a surfboard

Discussion in 'Electric Propulsion' started by Jcres, Apr 15, 2017.

  1. Jcres
    Joined: Apr 2017
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    Location: Finland

    Jcres New Member

    Hi,

    I am looking into making electric propulsion to a surfboard. I was thinking of using a brushless motor what are used in rc boats or aeroplanes. There are quite powerful motors and at this point I am totally puzzled what would be the power requirements in watts and what kind of propeller would be needed. I am looking into getting the surfboard up to 20 km/h / 12.5 mp/h speed.

    Any idea where to start? I am familiar with the rc electronics and can build surfboards but water propulsion is something I need to learn.

    Regards,
    J
     
  2. rasorinc
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    rasorinc Senior Member

    I would think you would want a water jet not a prop.
     
  3. Jcres
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    Jcres New Member

    It will not be a traditional surfboard and therefore water jet is most likely not suitable. I think I need more like a dive scooter type of a solution with a propeller.
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    So where are the batteries, controller and cables going to live on this surfboard?
     
  5. Jcres
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    Jcres New Member

    Motor will be in a pod and maybe the speed controller also. Batteries and rest what is left will be in the board.
     
  6. srimes
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    srimes Senior Member

    Sounds like sit-on-top kayak with a trolling motor, which works great but lower speeds and much heavier than your plan.

    And a prop is way more efficient than a jet, so that's good for battery life and range.

    My guess is you'd easily see the speeds you're looking for with a 3hp outboard. With electric power I'd bet 2KW would be plenty. Might even get there with 1 KW.

    If you already have equipment in that range you could slap it together and adjust based on what you find.
     

  7. Jcres
    Joined: Apr 2017
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    Jcres New Member

    Thanks for the reply srimes! I have a 3 kW brushless marine motor which I will then use.

    I just need a gearbox to bring the rpm down, what kind of prop would you recommend? With that I can then get some understanding of the optimum rpm range.

    Also anyone have any idea of the torque the propeller needs in terms of gearbox managing to take it without breaking it?
     
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