Mounting a transducer on an aluminum

Discussion in 'Boat Modification Journal' started by Redneck in a Skiboat, Aug 20, 2009.

  1. Redneck in a Skiboat

    Redneck in a Skiboat New Member

    South Caro
    I'm about to get a sonar for my jon boat. I'm tried of fishing blind. I have an idea how I want to mount the transducer, but before I do I'd like to hear from some of you guys. If you could post pictures that would be great. I have some aluminum flat stock that's a little less than an eighth inch thick. I was thinking about putting 2 pieces about 3" by 4" on, one on the inside and one on the outside the boat to add some support. My boat is beer can thin (not really but its close). If you have some "I wish I would did it like this" stories please share those.

    DANZIG New Member

    West Virginia
    "beer can thin"

    LOL! There are a couple of spots on my ten footer Jon that really are that thin! :eek:oooh::smile2:

    Are you talking a "glass" or "tin" boat?

    Either way, backing it up can't hurt. If nothing else, overkill gives you peace of mind. :big_smile:

    On my cuddy(tin boat) I reckon I am going to go with one of those "plastic" boards. Mount board to boat, transducers and such mount to the board.
    That way, if you change(or add) transducers and such, the new holes go into the board and not though the hull.

    Some folks "glue" the board on with 3M 4200 or 5200 to avoid holes altogether.

    On my Jon, I wanted every "add on" to be quickly removable for car-topping and the like, so I mounted the transducer to a "2 by" and clamp it on when I want it.

  3. 320hotrod

    320hotrod New Member

    I used one of the "plastic" boards also, the smaller one from Cabelas. I didn't really need it, but had the urge to buy something anyways:) The other method you described about sandwiching sounds like it would be fine also, just make sure to apply sealant beteween each piece, and also in each bolt hole you use to sandwich them together. Another thing if you go this route; make sure the screws you use to attach the transducer to the brackets go through all layers -- the outer aluminum, the boat transom, and the inner aluminum. That way the stress is applied from back to front evenly.
  4. StuBone278

    StuBone278 New Member

    south central Louisiana
    I don't really see why you would add support if the transducer is going to be mounted off the transom. This is what I found works:

    1 heavy duty steel C-clamp, some small PVC to go down the transom, a small "T" joint for the PVC, some screw-down hose clamps, a small 12 volt sealed battery, and an old little tackle box.

    Mount the fishfinder screen on the small tacklebox, running the wires inside to the battery, then have the transducer cables running into the box for a neat little package. I would take an upclose picture and post it, but I'm not at home so I can't do so. I found this picture that shows the outside of the mount from the first time I did it.

    Also when mounting the PVC with the hose clamps, make sure the PVC hugs the transom pretty tightly, not like it is on the drawing. The T-piece sits tightly against the transom in mine.

    Hope this helps.

    Attached Files:

    Last edited: Aug 22, 2009
  5. ShilohRed

    ShilohRed New Member

    West Tn
  6. catfishinsc

    catfishinsc New Member

    I had never seen or even thought about the plastic board before, but any I do from now on will have that. That way, if you change transducers, you won't have to worry about unused holes in the transom. I'd mount that with two bolts, probably 1/4", with the biggest washers I could find, and then screw the transducer to it. Seal the holes with 3M 5200 and use all stainless steel hardware.
  7. low desert jonathan

    low desert jonathan New Member

    FOLLOW THE DIRECTIONS YOU GET WITH THE UNIT. Take your time you can't go wrong unless your a imbecille. LDJ:roll_eyes:
  8. Flootie16

    Flootie16 New Member

    just make sure to seal around everything good inside and out when done
  9. Iowa_Josh

    Iowa_Josh New Member

    Central Iowa
    On my little boat, I ran a 1x2.5" board down from the transom board. I used a filler piece so it sat flat on the back of the boat and held it to the transom board with a couple of screws. No holes below the waterline, etc.
  10. DoubleD

    DoubleD New Member

    I just recently bought a “new to me” aluminum jon boat that had apparently had two previous fish finders. The last transducer and speed transducer were still mounted on the transom and when I removed them discovered several more old screws under them making a total of 8 holes /screw holes plus an additional 6 more where they has screwed the cables to the transom. Spent about $60.00 to the welder to repair all the old holes and about half a day running the boat back and forth to the welder. I plan on buying one of the clamp on style mounts, no holes in the transom to worry about if I ever decide to upgrade my finder. :roll_eyes:

    Transom Transducer Bracket.
  11. lendog

    lendog New Member

    berks, PA
    i've sent screws in my fiberglass and alum. boat and as long as ya calk um up good they'll be fine, i don't even think twice about puttin holes in the boat, calk fixes everything:wink:
  12. I really dig that cutting board thang boy. I gotta remember that.
  13. catman-j

    catman-j New Member

    Eastern Nebr

    I have to have everything on my boat removeable so it doesn't grow legs and walk away while the boat is sitting in storage. I attached mine to a 1 X 3 with a hole on one end. I have a long bolt that sticks out the back and all I do is put the board on and a nylock nut and washer. I keep 2 wrenches in my boat stuff to tighten the nut down but I'm thinking about the C-clamp idea.
  14. Pip

    Pip New Member

    I've got 2 mounted in the SeaArk. Both times I went straight to the transom. The only thing I did differently was use lag screws instead of the screws that came with the mounting kit. plenty of sealant around the holes. so far has never leaked.

    But using the poly board is also a good way to go too. Have seen a couple guys with that setup and seems to work good, also.