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Thru Hull vs In Hull Transducers

Discussion in 'Electronics' started by Aaron McCann, Nov 28, 2021.

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  1. Capt Ralph

    Capt Ralph Senior Member

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    I have learned in the AB ribs, that is a solid chunk of bilge glass in front of the transom. I have epoxied in a few transducers in this rib with good results.
    I make a round mini mold, tape it in well and fill it with epoxy, slow cure. A hour later, when all the air bubbles are gone, I slowly insert the puck ducer., ensuring not a chance of the smallest air bubble.

    I tried one Nirvana once,, no joy.
    Had to mount a transom ducer.
    Same display on both brands (Eagle digital) and the transom mount did work better plus speed and temp functions.

    These are lil boat bottoms and make a difference on a simple hull bottom. Larger boat mfgs can push the resin one way on Monday, push it another way Tuesday and backwards on Thursday. You will probably see a difference in all hulls when trying to shoot thru the hull.

    Can you hear me?
    Can You hear me now?

    Glad those who have an inside pucks, it is working.
    Still,,, Nothing beats an outside mounted and properly installed ducer.


    Now, a properly installed external ducer is another subject.
    Last edited: Nov 30, 2021
  2. Capt J

    Capt J Senior Member

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    I just set the transducer in bilge water and try it. If it works well that way. It will work well once epoxied in the same way. Slightly less effective as a thru hull, but a hell of a lot more effective than a POS transom mount. The transom mounts work just as well expoxied in the hull.
  3. Capt Ralph

    Capt Ralph Senior Member

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    I have not done hundreds of installs. Maybe 30-35 of many types many different ways, thru the many years. Many on my own boats.
    Direct water contact has always worked better and offers more options.
    Again, before we start to get excited, this is my experience. Your experiences may be different.
    All good.
    No ammonia broadcasting demonstration is required here.
    :D:D:D
  4. bayoubud

    bayoubud Senior Member

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    Had a 1kw 20 degree installed, it worked well with a Furuno Touch 2.
  5. Capt J

    Capt J Senior Member

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    yeah, I just have never had luck with transom mount reading above hull speed on any boat. Thru hull is the best, but in hull has always worked much better than transom mount in my experience.
  6. Pascal

    Pascal Senior Member

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    Transom mount on a RIB is way to fragile. Sooner or later it will get damaged on the chocks especially on the platform

    i installed a simple Faria depth gauge with a shoot thru xducer on my hatt a couple of years ago. Works great. Trying to remember... I think i epoxied the mount inside the hull and then used mineral oil.

    Never leaked.

    but it can only work with solid hull, not cored
  7. Capt Ralph

    Capt Ralph Senior Member

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    I learned, you have to get that ducer in the water, below the water/air that follows the hull surface. Like a thru hull, it is past the hull surface. Here is good clean water.
    I remember a transom adapter that offered a thru hull ducer on a ridged L bracket. This is when I learned about getting all ducers down in the clean water.
    Again, this has worked for us.

    Had one customer with this concern many years ago. Found a kick-up tri-ducer assembly that worked great. The Weaver chocks were no ware close but he was concerned about that just in case....
    Think it was a RayMarine unit.