Transducer cable routing

Discussion in 'General Maintenance/Repair Questions' started by Rapidroy5858, Jan 22, 2020.

  1. Rapidroy5858

    Rapidroy5858 Member

    76
    Sep 23, 2018
    LaPorte In.
    1990 searay sundancer 270
    Twin 4.3 mercruiser
    I will be installing a new Garmin unit in my 1990 sundancer 270 da .I am looking for tios or suggestions on running the tranducer cable from the stern into the bilge area and up to dash.
    A garmin rep. at chgo boat show suggested NOT drilling hole through stern but rather run it up and over then into boat. That does not seem right.
    Any help would be greatly appreciated.
     
  2. DWABoat

    DWABoat Active Member

    279
    Aug 13, 2019
    S Louisiana
    2001 280 Sundancer
    1989 220CC Cuddy Cabin
    Twin 4.3 w/Alpha Ones
    5.7 Mercruiser Alpha One
    Having just rebuilt a transom due to a bad seal on a drilled screw hole, I will do everything I possibly can to never never ever drill a hole in my transom.

    You can use Panduit from the lower transom to up above the water line, then drill the hole.

    As far as attaching to the transom, look for the small Starboard pieces that epoxy to the outside of the hull. You can attach the mount to that piece.

    Even at worse, if the transducer fell off, I will replace a hundred of them before I rebuild another transom.

    d
     
  3. BillK2632

    BillK2632 Well-Known Member GOLD Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    Running it up and over the transom would be ideal, but it would look pretty bad. As mentioned, mount the transducer on a piece of Starboard to prevent drilling into the transom, run the cable up above the waterline then drill the hole, epoxy the exposed core, put a clamshell over it and seal it with caulk.
     
  4. DWABoat

    DWABoat Active Member

    279
    Aug 13, 2019
    S Louisiana
    2001 280 Sundancer
    1989 220CC Cuddy Cabin
    Twin 4.3 w/Alpha Ones
    5.7 Mercruiser Alpha One
    Looks like BillK has had to rebuild a transom too!!!
    Listen to us on this one.
     
  5. Rapidroy5858

    Rapidroy5858 Member

    76
    Sep 23, 2018
    LaPorte In.
    1990 searay sundancer 270
    Twin 4.3 mercruiser
    Thats def more like I was thinking. since the garmin has boat speed built into it and the current speedo doesnt work very well I was considering using the hole higher up on the transome that the water tube grom the pitot tube runs through..id have to enlarge it of course..thoughts?
     
  6. DWABoat

    DWABoat Active Member

    279
    Aug 13, 2019
    S Louisiana
    2001 280 Sundancer
    1989 220CC Cuddy Cabin
    Twin 4.3 w/Alpha Ones
    5.7 Mercruiser Alpha One
    As long as any hole in the gel coat/fiberglass is above the waterline when the boat is dead in the water, you should be fine. Use the epoxy method mentioned. It is easy and gives a barrier between the water and wood core.

    Do you have screws in the transom holding the speed tube in place? That is where my rot began - the screw hole sealant eventually failed. It migrated out a couple of feet both directions. Ruined my whole transom. If so, get those things out and seal the holes forever. I would epoxy over them, if it were me.

    If anyone wants to complain about my little line running up the transom a little, then they are welcome to rebuild it when it rots out!
     
  7. b_arrington

    b_arrington Well-Known Member GOLD Sponsor

    Feb 21, 2007
    Setauket, NY
    2018 Back Cove 34
    Cummins QSB 6.7 480
    Sounds like a decent idea if you're not using the pitot tube anyway. Let holes in the boat. Be sure to use copious amounts of a good sealant, like Life Calk or 4200 (not 5200). Keep in mind that transducers don't like to have their cables modified (ends cut off), so you'll have to make the hole large enough for the end to pass through it. It shouldn't be a problem to seal that and attach a clamshell cover.

    I agree that routing the cable up and over the transom is silly for a boat of this type. The instructions that came with my transom transducer had directions for routing the cable through the transom, but well above the water line. I did that and still had no issues after 12 years.
     
  8. Rapidroy5858

    Rapidroy5858 Member

    76
    Sep 23, 2018
    LaPorte In.
    1990 searay sundancer 270
    Twin 4.3 mercruiser
    Thanks so much for the response.
     
    b_arrington likes this.
  9. Rapidroy5858

    Rapidroy5858 Member

    76
    Sep 23, 2018
    LaPorte In.
    1990 searay sundancer 270
    Twin 4.3 mercruiser
    I am thinking that where the pitot mounts now would be an ideal plave to mount transducer. I replaced pitot last year,resealed holes seemed ok.
    I think i would run the cable straight up and through an enlarged water tube hole , seal it all with the good 3m 4200
     
  10. Cocktail Time

    Cocktail Time Active Member SILVER Sponsor

    787
    Jul 9, 2007
    Lake Lanier, GA
    1998 400 Sundancer, Garmin 840xs GPS, Furuno RDP-110, B&G GPS pilot etc.
    Cat 3116's, Westerbeke 7.6kw
    As info, you can install a shoot through the hull transducer or I have seen (in my boat) where someone has siliconed the transom mount transducer in place inside the hull and I get great results without having to drill through the transom. Fish, bottom contours, depth and even temp all work. Until the motors heat up the bilge but I can live with that. Just an option. You can always try it and see if you like it.
     

Share This Page

Show Sidebar