DIY Electric Surface Drive

Discussion in 'Surface Drives' started by Irie, Oct 17, 2016.

  1. mydauphin
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    mydauphin Senior Member

    Yes, it is. I have to make a better diagram for myself. My boat is what is call semi-planning, it gets upto 14-18 knots, almost out of the water, but rather efficient there. The problem is docking, it turns into a nightmare there. Adding bow thruster and perhaps stern thruster too. If I can get the time and monies together.
     
  2. Irie
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    Location: Usa

    Irie Junior Member

    What materials are your tunnels made from? Will the extensions be made from the same material or something different?
     
  3. mydauphin
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    mydauphin Senior Member

    So far havent made them, project for next month, my best guess is I am going to make them out of aluminum.
     
  4. Irie
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    Irie Junior Member

    I put the 9.25x10 prop back on so I could get some continuous run time data. I did 2.6 miles, average speed was 13 mph with a max or 21 mph. The biggest issue I have now is the size of the lake. They lower the water level for winter so now I can run full throttle for only about 1 minute to maybe a minute and a half before I have to turn. One of these days I plan to run circles to get a realistic idea of range.

    https://youtu.be/Dz70rCmeT2w
    This video goes with the chart.

    Batteries and motor with cooling fan
    IMG_20161115_093447.jpg
     

    Attached Files:

  5. mydauphin
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    mydauphin Senior Member

    I love the work people do on electric boats, it is very interesting.

    One thought from the picture, you have the rubber boot with shaft right there. I would create a second cover on inside even if it not 100% water tight to slow the water entry down in case of that boot failure. Perhaps even a just metal plate with a hole in the center. A 1/4 inch hole is alot better than a 4-inch hole.

    Also, your circuitry is exposed. If your boat is like any of my boats, things will get majorly wet sooner or later for no apparent reason.
     
  6. Irie
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    Irie Junior Member

    It has definitely been interesting. I do have a second boot for the inside, I just haven't put it on. I'd like to have a smaller hole in the transom but then I would have to change a number of things. Its worked out very well so far. But yes, additional boots will be installed over the winter.

    In the picture yes, Its the BMS which I only use for charging. It is covered when the boat is running and I always remove the batteries after use.
     
  7. Irie
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    Irie Junior Member

    Been a while since I've updated this thread. The lake has been frozen for sometime now but I did manage to pull the motor mount and change the swivel plate before it iced up. Boat handling has improved with the new swivel and the entire driveline now sits 3/4" lower.

    I also reworked the 10.5 x 12 prop into a semi-cleaver. I lost a little top speed (.5 mph) but gained efficiency and the prop performs much better through the throttle range.

    Below is the last run before the ice arrived.

    Snapshot000002 (2).jpg

    https://youtu.be/bnRqIf6_nxQ
     
    Last edited: Jan 4, 2017
  8. tom kane
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    tom kane Senior Member

    Thats all the proof anyone needs, that you can have a Surface drive and a Subsurface drive all in one.
    A prop close to the transom.
    No need for a long tail boat drive and all that inconvenience
     
  9. mydauphin
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    mydauphin Senior Member

    Tom depending on your boat, prop size and speed, the prop has to be a certain distance from hull to avoid all kindness of problems. With my props moving then back further allowed me to stay in the water at the speed I run. There is a big hole in the water right behind my boats transom that would be a horrible place to put props or rudders. But 6 feet back, there is a big bump. And I benefit from shallower draft than having my prop under stern. Of course, on a smaller boat the number are much less.
     
  10. tom kane
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    tom kane Senior Member

    I understand what you are saying but having the prop close to the transom was no problem for Hickman`s sea sled.
    It`s not at all convenient to have a prop with a rudder 6 feet behind your transom.
    When you can alter the running level of your prop at will close to the transom you can run it in clear water under some pressure starting to rise to form your big bump.

    The difference of the running level of a prop in subsurface mode to surface mode is no more than less than half the diameter of your prop.
     
  11. Irie
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    Irie Junior Member

    Are your drives fixed? Would the props need to be so far from the transom if you could trim them?
     
  12. tom kane
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    tom kane Senior Member

    The main reason long-tail-boats have such a long shaft is because the shaft is so high on the transom, a long shaft is needed to get a shallower shaft angle for the prop to work and also to achieve better steering.
    With Burmese long-tail shaft which are set low through the transom the shaft can only be turned 10 degrees from side to side so a longe shaft is needed to steer better.
    These boats can have a shorter shaft.
     
  13. Irie
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    Irie Junior Member

    That makes sense, does the Burmese variant use a single u joint? If they used a double cardan u joint would they be able to increase turning while also being able to shorten the shaft?
     
  14. tom kane
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    tom kane Senior Member

    That is right Irie.
    The Burmese long tail from what I can find out is a single U/V joint only. Giving 10 degrees total movement

    If they used a double cardan shaft with a sliding spline they could turn 10 degrees each way, and also 10 degrees up and down.
    20 degrees of movement must be better than just ten.
    If they used a wide angle double cardan shaft with a sliding spline they could, have a greater amount of movement 360 degrees. Depending on the amount of movement the U/V joints were built for.
     

  15. Irie
    Joined: Jul 2016
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    Irie Junior Member

    I ran across this video today of a surface / subsurface drive. I've emailed the builder for more information regarding its surface piercing performance.
    https://youtu.be/U60rx06Dmtk
     
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