Keel cooling design for electric inboard

Discussion in 'Boat Design' started by yabert, Oct 6, 2025.

  1. yabert
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    yabert Senior Member

    Sadly, I can't see this video in Canada.
    Do you have another link or screen shot of this brass radiator.
     
  2. montero
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    montero Senior Member

    It's difficult . I paste Chinese version of great movie "Murphy's War " Due copy rights I can't find full movie at YT .
    You can watch this movie somewhere. At 0:28 scene there's brass radiator. Great movie btw.
     
  3. montero
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    montero Senior Member

    Primitive idea of cooling radiator by raw water looks nice .

    How do you and others guys think of efficiency water spray cooled radiator ? I know this way was used in motor sport for intercoolers . Vaporisation heat seems to be big.
     
  4. gonzo
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    gonzo Senior Member

    With salt water it will be fouled in minutes.
     
  5. yabert
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    yabert Senior Member

    I'm actually really happy with all I learn here and the fact I can build brass cooler for less than 100$.
    Sound to me like the best way to go to cool down my electric motors.
     
  6. montero
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    montero Senior Member

    For fresh water use it seems to be interesting .
    For salt water use it depend of kind of radiator , kind of nozzles . Honestly it tempting me to make some experiments . Easiet way is use a car without thermostat.
     
  7. montero
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    montero Senior Member

    Do you guys have knowledge about brass radiator build ? Are all of them cooper/brass radiators ?
     
  8. montero
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    montero Senior Member

  9. yabert
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    yabert Senior Member

    Man! Based on this article, my plan to use brass underwater is bad.
    Brass 272 tube contain at least 35% zinc and that will disappear under water...fu*k!!!
    Everywhere it's possible to read that brass 272 have good corrosion resistance. I bet that exclude salt water.

    Well, back to SS and his poor conductivity. I've even think another time about aluminum (good conductivity, cheap) with an anode. Why not?
     
  10. yabert
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    yabert Senior Member

    More information about brass in salt water (not good for my plan to use brass 272 tube):
    upload_2025-10-27_13-57-5.png
     
    Last edited: Oct 27, 2025
  11. yabert
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    yabert Senior Member

    I think I've find a really effective and low cost solution.
    A simple flush 1/8'' copper plate at the exterior and two 1/2 NPT 90° brass fitting weld on the copper plate to allow flow of coolant.

    I really like the small copper area and the cooler flush to the hull.
    But I'm a bit worried about the fact that cooler is hold in place with sealant. Well, sealant on copper and I can hold the cooler with some mechanism inside the hull (pic 3 and 4).
    Any thought?
     

    Attached Files:

  12. Heimfried
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    Heimfried Senior Member

    You pay too much attention to the heat conductivity of the metals and apparently don't notice the bottleneck of heat transfer you are creating with this sealing. It has to have some thickness to compensate different thermal expansion of the metal components and is a bad heat conductor. What you most need is area of heat exchange. Area is the key!
     
  13. yabert
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    yabert Senior Member

    Sure, I understand.
    Sealant is between hull and cooler, but don't interfere with heat transfer in my designs.
    The sealant is only around the coper plate (blue line) to seal water ingress. Brass fitting are weld on the copper plate, so the heat transfer is good (but, I admit, quite small).
    upload_2025-10-28_7-46-1.png
     
  14. gonzo
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    gonzo Senior Member

    I think you are getting a simple system and making it very complicated.
     

  15. yabert
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    yabert Senior Member

    And it's really sad as I'm huge fan of K.I.S.S.
    But in this situation, this solution seem more simple than typical saltwater + heat exchanger + dual pumps.
    My point is to find the most reliable solution instead of the most simple.

    It's maybe my lack of ''marine'' experiment, but I don't see how to design a simple and reliable cooler out of copper pipe.
     
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