homemade electric outboard

Discussion in 'DIY Marinizing' started by bnhk88, Aug 11, 2009.

  1. bnhk88
    Joined: Aug 2009
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    bnhk88 New Member

    anyone ever build their own electric outboard / trolling motor from scratch?

    i cant find any info anywhere ???..... so i turn to the best ;)

    thanks
     
  2. BHOFM
    Joined: Jun 2008
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    BHOFM Senior Member

    I have been doing some drawings using a 18V cordless
    drill and a 90`drive.

    I would like to build a prototype but don't want to spend
    a lot on proof of design model. Maybe this winter?

    It might be what the canoe, kayak people are looking for?
     
  3. Guest625101138

    Guest625101138 Previous Member

    Here are a couple I have played with:
    http://www.youtube.com/watch?v=2ul6hDx1L50&feature=channel_page
    http://www.youtube.com/watch?v=GJedBprmSkk

    The second one uses a 330g model aircraft motor. The first one has a Mars PMSM but is limited to about 280W by the little 12V batteries. The Mars motor can go up to 9kW with a suitable battery.

    There is quite a lot of discussion on this thread:
    http://www.boatdesign.net/forums/boat-design/efficient-electric-boat-27996.html

    Rick W
     
  4. CDK
    Joined: Aug 2007
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    CDK retired engineer

    The answer is YES.
    I made one because I had a low rpm brushless DC motor lying around for several years. Made a housing from stainless steel and even a multi-blade prop. Once it was ready I used it behind an 8 ft RIB a couple of times, but the fun was in making it, not using it.
     
  5. bnhk88
    Joined: Aug 2009
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    bnhk88 New Member

    i know you said use a low rpm motor but what size/type brushless dc motor would be needed?

    what kind of power supply would be most efficient deep cycle marine battery, lithium not really sure of the options.

    how do you determine how long the motor will run before all power is lost?

    would an electric scooter motor and battery be a viable source for my power plant?

    and finally how do you determine what kind/size of propeller to use in relation to the motor? it will be on my canoe. i would like to have a motor on each side.

    i just want to make a neat efficient propulsion system for my canoe because my friends are useless when it comes to rowing. i dont want to take the easy way out and buy two trolling motors i like building stuff myself.

    in addition my dad owns a auto salvage yard so i have a lot of parts at my disposal. i dont really know what parts if any would help me in my quest to propel my canoe

    sorry if im annoying im just a kid with a lot of questions that my teachers cant answer or even point me in the right direction. haha

    thanks again you guys are awsome
     
  6. BHOFM
    Joined: Jun 2008
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    BHOFM Senior Member

    Rick will most likely step in with some tech talk, but a lot
    of this is uncharted and you need to do so trial and error
    testing, and let us know the results.

    I think the scooter motor and battery would be a good
    starting place. The gear box is your next hurdle! Flex
    shaft is also an option.

    They make some large R/C boat props you might look at.

    Maybe a heat and air motor from a car??

    Or go to Wal Mart and get a trolling motor prop.

    For testing, maybe a 90` drill adapter?
     
  7. masalai
    Joined: Oct 2007
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    masalai masalai

    If you have a pet idea and an appropriate electric motor, "suck it and see" just for the fun of it... otherwise.... Why buy when there are soooo many commercial options? - If you have absolutely no information, why start here - do some homework (personal research first), then pose some questions....
     
  8. Guest625101138

    Guest625101138 Previous Member

    This video clip might give you an idea how a scooter motor works (give it time to download):
    http://www.boatdesign.net/forums/at...96419301-electric-boat-data-ve1_boat_9kph.wmv

    This thread has some some data:
    http://www.boatdesign.net/forums/boat-design/electric-boat-data-20445.html

    For prop design you can use JavaProp. A model plane prop will be about the best you can get - much better than typical boat prop for these light load applications.

    Rick W
     
  9. masalai
    Joined: Oct 2007
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    Location: cruising, Australia

    masalai masalai

    Ahhh now this is a different story, and far more in Rick Willoughby's field, where I would consider him to be an expert, be guided by him.... He is after high efficiency but you could utilise some of the technology to your advantage, like the long flexible external drive shaft (put the electric motor forward in a splash-proof box) - - maybe use a cheaper propeller or make your own 2 blade similar to that used by model aircraft but rotate at 300 to 1000 rpm in the water, salvage a controller from a busted electric outboard or make one up and salvage battery packs from busted electric drills (if the drill is busted the battery pack could still be OK, and the charger... - charge a dozen or so at home and when half are flat, time to head home:D:D:D
     
  10. BHOFM
    Joined: Jun 2008
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    BHOFM Senior Member

    When messing with the packs from the drills, wear safety
    glasses and keep a fire extinguisher handy!

    They pack a lot of quick power.
     
  11. CDK
    Joined: Aug 2007
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    CDK retired engineer

    This is what I meant in post #4.
    Found it in the shed today looking for something else.
    I made it at least 15 years ago, maybe 20. At the time it seemed OK, now I would have shaped it a bit differently. There also was a controller with a joy stick, but I'm afraid it went into the dumpster.
     

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  12. armourit
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    armourit New Member

  13. ben2go
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    ben2go Boat Builder Wanna Be

  14. tinkz
    Joined: Jan 2011
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    tinkz New Member

    I did a little "kids boat" with an electric scooter motor, inboard, direct drive through the skeg. motor was rated 250 watts, 2500 rpm on 24vdc. it did about 1/2 that on 12v.
    motor was about 4" diameter (10 cogs per rev = 5 windings?) and big on torque.
    shaft was 5/16 stainless rod and the stuffing tube was hard 3/8" brakeline tubing I'd grafted a vertical oiling tube to (gravity fed). clearance between the rod/tube was a happy .005 (about), it pretty well floated. it swung a young T-6 prop.

    long story short, those electric scooter motors are pretty impressive.
     

  15. nimblemotors
    Joined: Jun 2009
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    nimblemotors Senior Member

    I built one using an old broken 8hp output, replaced the gas engine with a 2.5hp (at 12v) pump motor that I ran at 36v (7.5hp).

    For a little boat, you might just try a cordless drill as-is, attach a prop to the drill and hold it underwater, just might work fine in water. haven't tried it myself.

     
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