Transom Mount vs trolling motor Mount?

[Scherbacj]

Tried searching but I think it’s too hard a topic to define with simple terms. Is there any advantage to running a 3-in-1 transducer from the trolling motor instead of the transom mount? 
 

I get my HDS Pro and AIHD 3-in-1 tomorrow and just wondering if I should look into trolling motor mounts or just put it on the transom? 
 

secondary question, in order to work with all my graphs I will have to hook the transducer to my bow graph and then hookup my console graph with Ethernet, if I run the transom Mount the cable will run the full length of the boat, should that cause an lag or other issues? The X-ducer has a 25FT cable so I don’t see why it would be an issue, but I am very new to electronics on a boat. 

[Alex from GA]

If you're going to put the head on the console put it on the transom; if the head is going on the bow put it on the front.  No issue with the cable lag or anything else.  I hope this is what you're asking.

[Scherbacj]

7 hours ago, Alex from GA said:

If you're going to put the head on the console put it on the transom; if the head is going on the bow put it on the front.  No issue with the cable lag or anything else.  I hope this is what you're asking.

That kind of answers my question. Since my “main” unit will be on the bow, but I already have a mount on the transom, I was just wondering if it was actually better to put it on the TM? I understand that my readings will be closer to where I fish from instead of 20 feet behind me, but does the image quality differ? How does Side Imaging/Down Imaging do if you are using the trolling motor? 
 

The only reason I want to run the Transom Mount X-ducer to my bow unit is because it’s an HD so I can’t run it directly to my Elite FS at the console without the module, so to save money & hassle I am going to run it to the HDS Pro and then just network the Elite FS.

 

Or, is it better to have the bigger & higher quality graph at the console? I figured it would be better to have the larger and higher resolution graph at the bow so I can see it better while actually fishing and so I can eventually add FFS, but am I thinking about this wrong?

[Tennessee Boy]

There is no problem running cables 20 ft.  These units are installed on much larger boats without issues.   I would put the transducer on the transom.  It was designed for that.  I wouldn’t want to have to put the trolling motor down to use side imaging.  Also side imaging will go crazy every time you turn the trolling motor if the transducer is mounted on the TM.    Put the bigger head unit where it best meets your needs.   Some people spend most of their time graphing at the console,  others spend more time with the trolling motor down.  It’s a personal preference.

[Bankc]

Cable lag isn't an issue.  That electrical signal in the cable travels at nearly the speed of light.  The sonar signal in the water only travels the speed of sound (in water), so it's the bottle neck here.  And even then, we're talking about 4859 feet per second.  Or about 0.12 seconds of delay in 300 feet of water.  The processor inside the sonar display is probably the biggest point of lag.  Besides, the cable needs to be that specific length for the sonar to work it's best, due to the impedance of the wire.   So if you're not needing the full 25 feet or whatever of cable, you're supposed to coil up the extra cable to keep the impedance the same. 

 

But generally, you want a transom mount for a console mounted graph and a trolling motor mount for a bow mounted graph.  The idea being, that the trolling motor mount will show you what's directly below you when you fish from the bow, instead of what's directly below the back of the boat.  And you want a transom mount for the console mounted graph because that's a good place to put it so it doesn't get knocked around when moving at faster speeds while driving the boat, which is when you'll be using the console mounted graph the most. 

[Scherbacj]

On 9/19/2024 at 7:19 AM, Tennessee Boy said:

.  I wouldn’t want to have to put the trolling motor down to use side imaging.  Also side imaging will go crazy every time you turn the trolling motor if the transducer is mounted on the TM.    

having to put the trolling motor down in order to start graphing makes sense, but if using the trolling motor will make the imaging go crazy then why are all the high end trolling motors building transducers into the trolling motor? 

Part of the reason I am asking if there is an advantage to having a x-ducer on/in the trolling motor is because I am looking to upgrade my trolling motor and one of the motors I am looking at (Tour Pro) doesn’t have enough length to add a x-ducer to it so I am wondering if I should go with a different trolling motor that either has the x-ducer built in or can at least have a external unit mounted to it. 
 

do you get better image quality from the trolling motor mounted unit? Or is the only benefit is the x-ducer is right under where you fish instead of behind you! 

[Tennessee Boy]

4 hours ago, Scherbacj said:

if using the trolling motor will make the imaging go crazy then why are all the high end trolling motors building transducers into the trolling motor? 

It’s turning the trolling motor that messes up side imaging.  If you intentionally go straight it will work fine.  The same thing happens with the transducer on the transom if you are making tight turns in the boat.  

 

4 hours ago, Scherbacj said:

do you get better image quality from the trolling motor mounted unit? Or is the only benefit is the x-ducer is right under where you fish instead of behind you! 

It’s the position of the transducer not the quality of the image. 

[gim]

2 hours ago, Tennessee Boy said:

It’s turning the trolling motor that messes up side imaging.

 

I have side imaging on my bow mount but I honestly cannot remember the last time I tried to use it up there, specifically for this reason.  It reads better when its not turning, and not turning a bow mount is a difficult thing to do.  Side imaging is a far better tool at the console when I'm moving along at 3-5 mph using it from the back transducer.  It gives a better feed back, sharper image, and since I'm not constantly turning, its more accurate too.  I use mine to locate isolated patches of boulders or rocks when smallmouth fishing.  I'll mark it on my GPS, and then approach it later from a distance and make a couple casts to it.

[Scherbacj]

13 hours ago, Tennessee Boy said:

It’s turning the trolling motor that messes up side imaging.  If you intentionally go straight it will work fine.  The same thing happens with the transducer on the transom if you are making tight turns in the boat.  

 

It’s the position of the transducer not the quality of the image. 

that makes sense, I just don’t understand why all these motor manufacturers are making motors with built in transducers with side imaging if it doesn’t work that great. I guess with the ghost, that’s how they make the Ghost 360 work, but the others it doesn’t make sense. 
 

I do understand wanting to have a tranducer closer to where you fish. 
 

 

[DaubsNU1]

On my old boat, I mounted the Garmin Echomap transducer on the bottom of the old 40lb Minn Kota trolling motor. Quickly realized I needed to keep the TM running straight in order to get good side imaging, but it did work. 

 

On the new boat, I do have side imaging on the bow mounted TM, but rarely use it.

 

Like @gimruis I use the console mounted finder and rear transducer to side image and mark brush piles, etc.