# Transducer placment



## whistler (May 20, 2012)

Looking around for the best place to mount a transducer. I think they say to stay 15 inches away from the engine area. Giving that info the first place I have to mount a transducer is between two strakes and right inline with a bunk board. I would like to use this spot and don't think it will ever contact the bunk but there is that remote possibility. The transducer looks like it's designed to fold up if it strikes something but is this reliable? The only time it would make contact with the bunk would be during loading. The next spot I could mount it is between the last strake and the chine. I'm concerned the chine will cause a problem and definitely be more susceptible to times when the transducer doesn't won't work due to the tipping in and out of the water during turns. I think I've covered all the bases so give me your thoughts.


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## Bob Landry (May 20, 2012)

I ran across the same problem because I dry stack my boat and I didn't want those guys to rip off my transducer with their fork-lift. The flip up mount is designed to flip when struck by something, but it depends on plastic tabs that are molded in the mount to secure it in place. It looks like those aren't built to take many hits before they wear down or just break off. I had the mount shown below made so that I could remove the transducer and lay it in the transom area when I finished with the boat. Everything is adjustable so once I got the depth setting correct for the transducer, I tightened everything down and when I put it in the water, I slip the center part down in the other part until the top is flush, tighten the thumbscrew and my transducer is set the same every time.


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## Frogman Ladue (May 20, 2012)

I just guessed and put it as far to the out side as I could. It seems to be a good spot. I'm not picking up any bubbles or cavitation.


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## whistler (May 21, 2012)

Bob Landry said:


> I ran across the same problem because I dry stack my boat and I didn't want those guys to rip off my transducer with their fork-lift. The flip up mount is designed to flip when struck by something, but it depends on plastic tabs that are molded in the mount to secure it in place. It looks like those aren't built to take many hits before they wear down or just break off. I had the mount shown below made so that I could remove the transducer and lay it in the transom area when I finished with the boat. Everything is adjustable so once I got the depth setting correct for the transducer, I tightened everything down and when I put it in the water, I slip the center part down in the other part until the top is flush, tighten the thumbscrew and my transducer is set the same every time.



Sure is a nice looking piece and some good thinking on your part! I like your idea. A Question for you! Looking at the design it appears you have only one thumb screw holding the adjustable sliding plate in position. Does that ever come loose after a days hard operation? Can you post some general dimensions and add anything you might change if you did it again. Thanks


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## Bob Landry (May 21, 2012)

One thumbscrew does fine. When it bottoms out, you can get a little "tweak" on it and it seems to seat OK. I have not had it come loose, but the cable is secured and if the thumbscrew were to back out, the transducer would only dron 1/4" or so, so it's no big deal. I attached the PDF drawing of the mount.
View attachment transducer mount.pdf


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## PSG-1 (May 21, 2012)

I've played around with trying to mount the transducer in the right place on both my jetboat, and on my 16 foot triton. On both boats, as soon as I come up on plane, it no longer reads depth. On my mom's boat, an 18 foot Sea hunt, you can run at almost full throttle before it quits reading. All 3 boats use the same fishfinder, a garmin 160C. So, why can't I get them to work on my aluminum boats? Does it have something to do with a metal hull vs. a fiberglass hull?


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## Gramps50 (May 21, 2012)

PSG-1 said:


> I've played around with trying to mount the transducer in the right place on both my jetboat, and on my 16 foot triton. On both boats, as soon as I come up on plane, it no longer reads depth. On my mom's boat, an 18 foot Sea hunt, you can run at almost full throttle before it quits reading. All 3 boats use the same fishfinder, a garmin 160C. So, why can't I get them to work on my aluminum boats? Does it have something to do with a metal hull vs. a fiberglass hull?



When I was talking to the salesman at BP he told me that the Gramins had issues with reading at speed. I would think that if it had anything to do with the difference between fiberglass & aluminum. Might have something to do with the shape of the hulls. 

I had the issue with my Eagle loosing depth at speed and I finally got it working pretty well by remounting the transducer, it 15" from the prop and I placed it in between the ribs. I also mounted it on a1" cutting board so I could move it if need be. Before the remount if I lost depth I would have to come to a stop to regain it. Now I can slow down a little and it will normally come back.


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## whistler (May 22, 2012)

Bob Landry said:


> One thumbscrew does fine. When it bottoms out, you can get a little "tweak" on it and it seems to seat OK. I have not had it come loose, but the cable is secured and if the thumbscrew were to back out, the transducer would only dron 1/4" or so, so it's no big deal. I attached the PDF drawing of the mount.




Thanks, for the diagrams. Now my only problem is living where you can whizz in your yard  . There are no machine shops nearby so I'll take a drive and see if I can find someone who machine that for me. Again Thanks!


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## PSG-1 (May 22, 2012)

whistler said:


> Thanks, for the diagrams. Now my only problem is living where you can whizz in your yard  .



I whizz in my yard all the time, and there are houses all around me. :mrgreen: Of course, my entire yard is bordered with trees, so, I have a natural privacy fence.


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## Bob Landry (May 22, 2012)

The guys's name who made it for me is Jerry Breedlove. His email address is [email protected] . The cost for the mount was $100 including shipping to me, which I thought was very reasonable. I checked at local machine shops and everybody wanted $150 or more plus tax.


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## Gramps50 (May 23, 2012)

PSG-1 said:


> I whizz in my yard all the time, and there are houses all around me. :mrgreen: Of course, my entire yard is bordered with trees, so, I have a natural privacy fence.



Isn't that how you are suppose to water the grass? :?:


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## whistler (May 23, 2012)

Gramps50 said:


> PSG-1 said:
> 
> 
> > I whizz in my yard all the time, and there are houses all around me. :mrgreen: Of course, my entire yard is bordered with trees, so, I have a natural privacy fence.
> ...





I know your post was directed toward PSG-1 but it sounds like something my wife used to say until she got used to me doing it...........Now she's jealous! :wink:


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## PSG-1 (May 24, 2012)

Gramps50 said:


> PSG-1 said:
> 
> 
> > I whizz in my yard all the time, and there are houses all around me. :mrgreen: Of course, my entire yard is bordered with trees, so, I have a natural privacy fence.
> ...




Not sure, but my theory is that there's no sense in wasting water to flush a toilet, when you can pee outside. :lol: 

However, I would NOT recommend 'fertilizing' the front yard. LMAO


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## whistler (Jun 17, 2012)

Well I went ahead and mounted my transducer the more traditional style for know. I couldn't find a anyone around here that could reproduce the bracket of B. Landry's in his drawing. I still hope to do that sooner or later. 

Got out on the water and all is working fine on the FF but I do loose side imaging at almost any speed above 3-5 MPH. I'll figure that out later but my question is.........Do these things (transducers) usually leave such a rooster tail? When I operate on plane there is a rooster tail higher than the outboard coming from the transducer and faster = higher. Looks strange to me but may be normal. Was concerned that I might have it mounted too low in the water? The transducer is just below the bottom edge of the boat on the trailer but when loaded and in the water the boat is nearly half under water itself making the transducer even deeper. What are your thoughts and opinions?


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## Gramps50 (Jun 17, 2012)

I don't think the transducer should be making a rooster tail, I think it's to low in the water, if I'm not mistaken. For the most part the center line in the transducer should be even with the bottom of the boat and level with the water. 

Mine doesn't rooster tail, WOT & 25 mph


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## Bob Landry (Jun 17, 2012)

I also had a rooster-tail problem and it was so bad it was spraying on the side of the motor. I even moved it to the other side thinking that maybe it was prop wash causing it. I finally raised it to where the bottom of th transducer was about 1/8" below the bottom of the boat and the problem went away. I still don't get a reading at high speed, but I think that takes a different style transducer.


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## shawnfish (Jun 17, 2012)

Bob Landry said:


> I also had a rooster-tail problem and it was so bad it was spraying on the side of the motor. I even moved it to the other side thinking that maybe it was prop wash causing it. I finally raised it to where the bottom of th transducer was about 1/8" below the bottom of the boat and the problem went away. I still don't get a reading at high speed, but I think that takes a different style transducer.



what kind of FF do you have? ive never seen one that does not read at high speeds... and your ducer should be mounted about 1/8 inch below hull, so the water from ur hull runs smooth over the bottom of the ducer....


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## whistler (Jun 18, 2012)

Gramps50 said:


> I don't think the transducer should be making a rooster tail, I think it's to low in the water, if I'm not mistaken. For the most part the center line in the transducer should be even with the bottom of the boat and level with the water.
> 
> Mine doesn't rooster tail, WOT & 25 mph




Gramps50, I never noticed the old transducer throwing a rooster tail either. This side imaging transducer is a lot larger than the old one (both hummingbirds). I was on a lake all last week and tried to look at everyone I could as they launched but was unable to find a aluminum boat with a side imaging transducer to compare. Might be a good reason to call their Customer Service???
It's a possibility I have it mounted a little low as you suggested!


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## RivRunR (Jun 18, 2012)

The HB side imaging transducers take a *lot* of tweaking to the mount location and angle to be able to get decent 2D readings at speed, especially on tin boats with rivets, etc. I finally gave up on moving mine and just added a second, 2D-only, transducer, which when connected to the head unit with a "Y" cable, eliminates the 2D feed from the SI transducer. By doing that I was able to raise my SI transducer well above the bottom of the boat (to avoid it ever hitting anything) while still getting good 2D readings at speed.

_Edit: Here's a pic of my setup...not the greatest angle for seeing the height, but the SI transducer (starboard) sits about 1/2 - 3/4" above the bottom of the boat, and the 2D sits below the boat. I could have set the SI much higher, but I was afraid the signal would bounce off the 2D transducer._




The rooster tail on some of the HB SI transducers comes from the design of the mount bracket having a hole/gap in it, and for some models there is an HB plug which fixes it. Some ppl have used silicone to close the gap, some have put a plate over the mount so the rooster tail is deflected, etc, etc.

There's a lot of information about SI transducer placement on the Humminbird Side Imaging Forum


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## captnchris (Jun 27, 2012)

Did you know that hull design, including aluminum (tin boats) assembled with rivets has nothng whatsoever to do with your external high speed or imaging transducer sounding? A row, or even a triple row (or more) of round rivets heads smattered across your transom have simply become an excuse for a poor resultant transducer sounding. A trailing transducer, adjusted flush with, or even below the bottom of any running surface, tucked up tightly to the transom, is forced to plow with stern down as the boat displaces water and moves at speed. The dynamics behind a fast moving boat are tremendous. We're taught to cause the transducer to plow below the running surface and is most often fatal. We must think about what actually occurs back there. The accompanying basic transducer bracket oftentimes fails us and will not permit the correct latitude of adjustment and location for an optimum sounding. Roostertails, garbled or grayed out screens, rubber plugs, silicone and electrical tape become the norm when ALL are all unnecessary. Unfortunately, we've been forced to resort to all manner of shade-tree "fixes" (often exacerbating the problems) and forum help from others. If your electrical is correct, including guage and run, and your electronics work properly at drift, a correctly installed external transducer will sound at optimum on any boat at any speed. 





(June 24, 2012; New Starcraft Islander, new Humminbird installation, perfect marking all speeds , no roostertail...no installation damage)


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## whistler (Jun 28, 2012)

Captnchris, I had to reread your post a couple of times and then think about it. I'm kind of slow and some of what you said goes against what the mfg tells us. So it took a while to digest! That's not to say you're not right as I've found out many mfgs will use any excuse for their product that is not performing as they say it will. They certainly are slow and/or not willing to admit fault or take blame in very many situations. It's usually their motive to try and convince the consumer it's their fault by improper mounting or operator error etc.......! I would like to see more pictures of your transducer mounting from various angles to help me grasp what you have done. Thanks!


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## TOY BOAT (Jun 29, 2012)

Mine produced a rooster tail as well. It was mounted correctly.


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## captnchris (Jun 29, 2012)

*whistler.........*Marine electronics manufacturers we depend on are the best in the world and that's exactly what they do. They build high quality electronics, they don't install them. In fact, troubleshooting installation and optimization of your transducer will comprize the majority of all marine electronics related issues. I would rather believe they are not "passing the buck" because there are so many factors that create the inevitable issues which can occur before the transducer is ever installed. If it isn't the damage the installation creates, it most certainly will pertain to the sounding. Your high speed transducer is purposely designed to skim or "surf" to operate at spec. That said, I do defend them, as the manufacturers provide the basic information and installation equipment _(with disclaimers and caveats)_ and I fail to believe they have any other motive than to provide information as they understand it and have been trained to disseminate. 

Oftentimes, the simplest solutions and reasons for causes are the least obvious and, of course, the least understood when it pertains to the installation and optimization of external trailing transducers. These high speed x'ducers are skimming transducers, not plowing transducers. Some find that by installing them as directed below the running surface, they operate to suit...the majority will not. Nature was kind enough to provide displaced and elevating water behind a fast moving planing or displacement hull. 

*Note: The Starcraft Islander pictured is not our boat; however, its owner has correctly made his Humminbird installation to operate at spec all in the spirit of avoiding typical hull penetration and damages. 

*TOY BOAT.......*A rooster tail is evidence enough that your transducer is NOT installed correctly. It merely indicates that you have installed it in accordance with its accompanying instructions.


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## Jonboat Jerry (Jul 5, 2012)

I have the 798ci SI combo as well and I couldn't be happier with it. It did take a little transducer tuning to get the rooster tail
down. I also poured over the 798 forum on the unofficial H.B. websites.
https://www.xumba.scholleco.com/index.php 
https://forums.sideimagingsoft.com/
https://www.jasonhalfenoutdoors.com/HumminbirdIndex.html

To begin, the washers on the mount have to be set to the correct transom angle. This angle can vary + or - depending on
the angle your boat planes. (The seam on the transducer should be parallel to the water flow coming off the transom at speed.)





To solve the Rooster tail problem, start by getting it up as high as the mount will allow and no 2d signal at speed and no R.T. 
mark the location. Adjust the transducer down in 1/16" increments until the 2d reads reliably. There may be a small R.T. but
that's as good as it gets. Other factors are, 455 & 83 khz sensitivity, surface clutter, and noise filter settings.




As for Si and Di, the manual says 2-6 mph are best. The boat has settled into the water and hull turbulence is nil. Chart speed should be same as boat speed.




I have included pics of my setup, you can barely see the seam in the 'ducer. Notice that I have the mount attached to a piece of PVC board spacer that is beveled on the bottom to prevent turb. This gets the ducer away from the transom similar to the offset on a jack plate. I still have a small R.T. but I can live with it.
I'm envious of your sunken boat finds, the only thing around here to look at is ROCKS!


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## whistler (Jul 6, 2012)

Jonboat Jerry said:


> I have the 798ci SI combo as well and I couldn't be happier with it. It did take a little transducer tuning to get the rooster tail
> down. I also poured over the 798 forum on the unofficial H.B. websites.
> https://www.xumba.scholleco.com/index.php
> https://forums.sideimagingsoft.com/
> ...



I was able to get this set OK according to the instructions given with the unit and how to measure the angle. 



Jonboat Jerry said:


> To solve the Rooster tail problem, start by getting it up as high as the mount will allow and no 2d signal at speed and no R.T.
> mark the location. Adjust the transducer down in 1/16" increments until the 2d reads reliably. There may be a small R.T. but
> that's as good as it gets. Other factors are, 455 & 83 khz sensitivity, surface clutter, and noise filter settings.
> 
> ...



This is what I'm going to work on. Thanks for the pictures.



Jonboat Jerry said:


> I'm envious of your sunken boat finds, the only thing around here to look at is ROCKS!



Yea, I've got to say ROCKS would be boring! It was actually pretty exciting to see the two vessels. I've let my mind wander as to what could be attached to them or is in them and the whole story as to what happened. 60' of water I don't suppose I'll ever find out?


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