Pontoon boat and deck boat magazine
home
+ Reply to Thread
Page 1 of 2
1 2 LastLast
Results 1 to 10 of 15

Thread: Transducer placement

  1. #1

    Default Transducer placement

    When running over 15 knots i lose my bottom reading. I currently have it attached to 3"x5" on bracket back of toon.
    I tried moving up to top of bracket and it made it worse, it gave me a rooster tail going to try moving it to bottom of bracket but I was pretty close to that before moving it. Would one add piece of aluminum stock to extend bracket.
    Thanks for any replies
    Hoejef

  2. #2
    Join Date
    Aug 2019
    Location
    Central Texas
    Posts
    215

    Default

    Your depth-finder Owners Manual probably has some guidance on this.

    The transducer must stay in constant contact with smooth water to operate. Take a straight-edge like a carpenters’ level and place it on the bottom of the ‘toon which has the bracket attached. Allow the level to extend aft to your transducer. Look at how your transducer relates to that level.
    The bottom of the transducer should sit exactly on that extended level…. and the forward edge of the transducer should be about 1/10th inch higher than it’s trailing edge.

    Even so…at some speed the depth-finder may be incapable of receiving it’s own transmittals. My Hummingbird Helix 7 will “play” fine up to about 30 mph at which point it fails to indicate…. probably due to either wake turbulence or the units’ loss-of-timing synchronization. (transmitted signal returning-echo too late for transducer which is farther down the lake before the echo returns.)

    Hope that helps.
    2015 SouthBay 522FCR w/150 Yamaha

  3. #3

    Default

    Thanks Foghorn
    I moved it yesterday similar to what you mentioned and had better results I think I need to fine tune just a bit more, but have a feeling that's going to be as good as it gets with all the turbulence that goes on back there.
    Thanks Hoejef

  4. #4
    Join Date
    Feb 2014
    Location
    Boat at Lake of the Ozarks Missouri
    Posts
    709

    Default

    Just a reminder that as your speed and depth increases it takes some for the signal to "bounce" back to the transducer.

    So....the level theory of transducer placement, even a 1/10" tilt may need to be increased to something more like a 1/2" forward tilt.

    Works fine up to xx MPH is always the clue.

    I'm just sayin - from experience.
    Captain Tony
    2005 Summit by Triton - 220T Platinum 3Log
    2005 115HP Mercury Optimax - 228 Marine Master Trailer
    St. Louis & Lake of the Ozarks, MO.

  5. #5

    Default

    It keeps getting better each time I adjust it.
    I have at this point bottom # constant at all speeds just losing bottom picture.
    At this point I am flush with bottom of toon and going opposite of what you said , but will try your suggestion makes good sense.
    Does increasing scroll speed relate to keeping bottom picture.
    Thanks for all the good replies

  6. #6
    Join Date
    Feb 2014
    Location
    Boat at Lake of the Ozarks Missouri
    Posts
    709

    Default

    Well think of it this way. The transducer is responsible for sending out a signal to the bottom or fish etc.
    So it stands to reason that it must receive a signal back to tell you what it sees.

    If it is level or angled past the keel level then it will work as long as it can get the signal back.
    But we keep going faster and soon the signal arrives at a point after the boat has left the area.

    If you angle the transducer slightly toward the forward area, (slightly @ 1/2" or so) then the
    signal that comes back may still find the boat in the area to decode and display what it sees.

    Works well but requires a little trial & error and adjustments. Then run at speed.
    Captain Tony
    2005 Summit by Triton - 220T Platinum 3Log
    2005 115HP Mercury Optimax - 228 Marine Master Trailer
    St. Louis & Lake of the Ozarks, MO.

  7. #7
    Join Date
    Aug 2019
    Location
    Central Texas
    Posts
    215

    Default

    I view it differently than what I think I’m reading here.
    Firstly, sound travels faster in water than in air… Additionally, the “ping” transmitted by the transducer spreads out as it travels toward the bottom…. then the echo actually “mushrooms” as it bounces back up off the bottom. By the time it reaches back to the transducer….the little “ping” which was only 3 square inches wide when it left the transducer… returns to an area many square Yards larger. It would take a boat travelling at super-sonic speeds to miss that echo even in depths less than 1500’.

    The primary reason to have the leading edge of the transducer slightly higher than the trailing edge is not to project the beam “ahead” to ensure capturing an echo. It is to prevent turbulent air from getting beneath the transducer in order to maintain contact with smooth water. (think of a flat-bottom water ski gliding on top of the water as opposed to a wash-board creating air-bubbles beneath itself.)

    hoejef, increasing scroll-rate will add updates to the bottom while travelling at speed… but it does so at the loss of structure-details. It may help to think about what data is most important to you. When I’m moving at speed I’m not searching for structure details…I’m more interested in depth for clearance purposes. If I’m curious about studying structure beneath the boat…. I’d slow down to trolling speed or less to obtain that level of detail.

    I’m not an expert on this… I only know what works for me…. but there are some excellent videos online produced by mfr’s and professionals I’m sure you can search for.

    Hope this helps.
    2015 SouthBay 522FCR w/150 Yamaha

  8. #8
    Join Date
    Jul 2006
    Location
    Raystown Country, PA
    Posts
    2,337

    Default

    Transducer placement on pontoons is really hard to get unless you have a bracket that lets you get close to both the rear surface of the tube and down to the bottom of the tube. Most of the brackets are actually there for mounting a pump, so they are up out of the water underway. If you are not right at the rear of the tube, it is hard to tell what happens in the little gap you end up with. The answer is you mess with it until you get the best result for your boat. I have flipped the transducer bracket over and mounted it on the bottom of the tube bracket and gotten good results in the past.

    I pulled my old Lowarance Elite 7 out of a toolbox drawer yesterday, stuck the transducer on the bracket on this 1992 boat and put screws in two holes that lined up. I ran the 'ducer wire up through the deck and threw everything else in a tote. Once we got to the lake I pulled the panel off and wired it up. We ran it from 0 to 25 mph at 17 mph average, in 0 to 100 feet of water, for about 25 miles yesterday and today, and never saw it lose the bottom once. I guess I'm either an expert or just lucky.
    1992 Tracker Party barge 24 (new deck, carpet and interior, 2019)
    1996 Mercury 115 ELPTO
    1983 Sea Nymph FM171 Striper
    1985 Johnson 70 J70ELCO

    Raystown Country, PA

  9. #9

    Default

    All good info, my best results have been flush with bottom of toon with leading edge just up 1/8 ish and that gives me readings on the high end 23-25 kts. Picture at that speed fades but still there and that works for me. Unlike a planning hull you can stick your head over the stern and almost see where it needs to be placed, like mentioned with a pontoon there's just so much turbulence. Luckily my transducer is able to get far enough down the pump bracket .
    Thanks all
    Hoejef

  10. #10
    Join Date
    Aug 2019
    Location
    Central Texas
    Posts
    215

    Default

    Here’s pics of my Helix 7 transducer which I installed to replace the Helix 5 previously installed. (The 5 didn’t have GPS and I wanted mapping capability. Anyone wanting a virtually New Helix 5 with all the bells and whistles except gps can make me a reasonable offer ($150 suggested) and I’ll pay shipping.)

    Anyway…. I mounted the Helix 7 transducer where the 5 was previsously…. but slightly lower. As you can see, it descends slightly below the bracket on my right ‘toon… but it reads at speeds up to 30 mph and I’m happy with that as I rarely push it any faster than that anyway. Notice the leading edge is higher than the trailing edge. Hope this helps.
    Attached Thumbnails 0AD6FB06-E8D3-4418-9AED-4BB8DDF6CECE.jpg  
    Last edited by FogHorn; 07-03-2021 at 04:34 AM.
    2015 SouthBay 522FCR w/150 Yamaha

+ Reply to Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts