Anyone Used a Trolling Motor as a Towed Generator?

Discussion in 'OnBoard Electronics & Controls' started by Yobarnacle, Dec 16, 2011.

  1. Yobarnacle
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    Yobarnacle Senior Member holding true course

    To repeat question in thread title, "Anyone Used a Trolling Motor as a Towed Generator?"
     
  2. Yobarnacle
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    Yobarnacle Senior Member holding true course

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  3. pistnbroke
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    those are not theorists yobaracle they are ignorant idiots ,,,,,,yes if you can get it to spin youwill get and output BUT I question what prop you will need on it .certainly not the one it came with ..If it was me I would be putting a biggerpitched prop on it and runnig it on a pole along the side of a swimming pool or holding it over the side of a power boat....you need to know the speed you are to run at ....then the revs it will do ...1000 from my experiments and work out the prop pitch with about 60% slip...
    probably about 10 pitch from my mental calcs....did you see this ....yes its a model areroplane prop and gave an 88% increase in range with the same boat speed ....
     

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  4. Yobarnacle
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    Yobarnacle Senior Member holding true course

    Are you using the airplane prop for propulsion? or for generating? Interesting. I'm using two of the prop pictured on my doubled Minn Kota 160 Riptide trolling motors for propulsion.

    You mentioned 10 pitch. These seagull hydrofans are compound pitch, averaging 10 inches. They are 5 bladed, 11 inch. The squared off blade tips fit nicely the Kort nozzle style prop guards I'm using. In your opinion, would these props and pitch work as dynamo helixes? Would the Kort nozzles aid? or detract from genrating speed?
     

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  5. pistnbroke
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    not much you can tell me about British Seagull engines ..I have the same prop on a silver century in my shed + other gulls !!! I n the end mate the only way you will tell is to try it hanging off a power boat ....How did you get a seagull in Mexico ???!!!

    a picture of your minn Kotas with these props would be great ...aero props for propulsion..never heard of a minn kota being used for a generator ..though it should be no problem but how efficient

    Great work on the Iranian l/b post ...oops
     
  6. gonzo
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    gonzo Senior Member

    You can connect a variable speed electric motor or a gas motor and measure the output at different RPM's. That will give you the pitch at the expected boat speeds.
     
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  7. Yobarnacle
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    Yobarnacle Senior Member holding true course

    Thanks Gonzo. Always glad to have your thoughts.
    pistnbroke, I'm gonna forget the Irate-an. Got my panties in a wad when he said he wouldn't permit criticizm. NOT GONNA PERMIT FREEDOM OF SPEECH?
    Enuff. Pass.
    I'm american born n bred. My wife is mexican.We own property in both countries. Our project boat, an Albin 25 (stretched to 30) is an electric motorsailer stored in Florida. We change country every 3 to 4 months. Currently we are in Mexico. I have 2 seagull 4:1 red lower units, and 4 five bladed hydrofan props, all bought in states. I don't have many photos of IntrepiDos. I was/am feeling my way in her refit. Most of the photos I have are on my cell phone and I don't have the cord to upload to my computer. You can see a lot of info about IntrepiDos on my thread, Alternate Motorsailer Rig
     
  8. pistnbroke
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    Well I have a rev counter on my Minn Kota ..on 12v in air it pulls 650 rpm and in water 500 at 20 A on 24 v you are talking 1250 /1000 rpm at 50A

    so I think spinning it with a variable speed drill and then knocking 25 % off for when loaded ...or put a headlight bulb on it would give a good guide ..dont forget a diode if you want to test charge a battery or it will try to motor .....and then we will be into series regulators ....ouch ..

    Seagulls were never red ....the place to look for all things seagull is http://www.saving-old-seagulls.co.uk ..moderatorand owners a funny bunch very easy to upset if you get inventive or modern ...a clique if ever there was one...I have electronic igniton on my magneto model and a pit bike carb ..oh boy they dont like that .....
     
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  9. Yobarnacle
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    Yobarnacle Senior Member holding true course

    red gears aren't colored crimson. 4:1 red is read as 4 to 1 REDuction. :)
     
  10. pistnbroke
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    Location: Noosa.Australia where god kissed the earth.

    pistnbroke I try

    Yes brain must have had a mis function ..I know its 4 :1 bit useless really as it limits he speed of a small boat to about 4 kts ..I have removed the silver century head and put it on an AD gear case 2.5 :1 which gives about 8 mph on a 12 ft boat but no clutch ....bloody useless dangerous things in my opinion on a busy seaway. Too noisy and need to be flat out all the time ...not enough power to exceed displacement speed and get on the plane
     
  11. Yobarnacle
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    Yobarnacle Senior Member holding true course

    I bought the units to get the props. I know the hydrofan is old technology. So is the sextant. So are knives, forks, and spoons. Somethings are utilitarian and classics.
     
  12. Yobarnacle
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    Yobarnacle Senior Member holding true course

    Your experiment concurs with my real world motorsailng data. With the hydrofans and Kort nozzles on the Minn Kotas, on a beam reach 10 kt breeze, 4 to 6 inch chop: I get 4.5 kts under main sail alone. With 12 amp 24v assisting, spinning Minn Kotas props, I get 6.1-6.3 knots. Almost all of this is eliminating the drag of the props. I estimate they slow sail speed by 1.5 knots. They are no longer dragging when under power but contributing small amount additional thrust. 30 amps imput I get 7 kts. Hull speed. Under power alone, no sails, 30 amps gives me 4 kts. 60 amps gives me 6.5 kts +/- power alone. On a close reach 20 kt wind, motorsailing 60 amps, I saw 8 kts. The Minn Kotas can accept 116 amp 24v power. Haven't revved them that high. Don't plan to, except in an emergency all astern. :) The hydrofans weigh many times the plastic props came with Minn Kotas. I don't want to over stress the motors. I'm real pleased with the thrust/speed I saw.
    Now, if they'll generate electricity when I'm anchored overnight in a current in a river? Hooray!
     

  13. Yobarnacle
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    Yobarnacle Senior Member holding true course

    Since you have a Minn Kota and a Hydrofan prop, you may want to try it yourself. To adapt prop, I found/purchased off the shelf stainless tubing, 1/2 inch OD and 3/8 inch ID. 1/16 inch wall. This sleeved the 3/8 inch Minn Kota shaft for the half inch shafted seagull prop. Minn Kota uses a pin in a slot, seagull a spring. Instead of widening the slot, I ground a little on the tab end goes in the slot, of an old seagull spring. I use a nylock nut instead of the Minn Kota wing nut to keep it all on shaft. I had to bush the hydrofan prop away from the motor housing to prevent rubbing. I cut 2 washers out of a plastic cutting board with a hole saw. They go on shaft first, then hydrofan, then spring, then nut. Tada!
     
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