Side Imaging - Left side image and prop distortion

[Junger]

I have the rear transducer mounted right of the engine on my boat. When I'm going about 5mph, the right side looks fantastic, but left side shows nothing. When I slow down to about 2mph the left side will start to show data. This is with the engine trimmed up enough to not interfere with the transducer. 

 

Is that normal? Is it just caused by prop wash? 

[Tennessee Boy]

I see some noise near the transducer when my prop is turning but it doesn’t affect what I see at a distance.  I would guess that the left side of the transducer is out of the water when you get up to speed.

[slonezp]

Yes it's normal. If the motor is trimmed down blocking the transducer you end up getting a reflection of what's on the right side only darker. Trim up the motor or get a 2nd transducer for the port side and a Y connector.

[Junger]

3 hours ago, slonezp said:

Yes it's normal. If the motor is trimmed down blocking the transducer you end up getting a reflection of what's on the right side only darker. Trim up the motor or get a 2nd transducer for the port side and a Y connector.

 

Weird thing is, it's trimmed up enough that it shows data at 3mph, but when I go about 5mph, it goes dark on the left. I'll just add a port side transducer and be done with it, trolling on the big engine to graph at 3mph is painful!

[Tennessee Boy]

Can you post a picture of how your transducer is mounted?  

[Junger]

7 hours ago, Tennessee Boy said:

Can you post a picture of how your transducer is mounted?  

 

It's backed into the garage, but I'm taking it out tomorrow and I'll be able to get a better picture. I suspect it might be too far up from the center pad.

[A-Jay]

I had the same deal with the original Optimax motor.

Not the motors fault, there just wasn't sufficient clearance

for the transducer to get a clear unobstructed view. 

Dealt with it for a couple of years.

Only way to 'fix' it was to trim the motor way up and go slow.

Once I repowered to the ProXS I added a 6 inch manual Jack plate

mostly to get the OB the heck out of the way.

Worked like a champ.

Talked about here ~

https://www.bassresource.com/bass-fishing-forums/topic/205586-re-powering-the-lund-1875-pro-v-bass-boat/?do=findComment&comment=2346507

A-Jay

 

[Junger]

On 5/18/2022 at 7:10 AM, Tennessee Boy said:

Can you post a picture of how your transducer is mounted?  

[Tennessee Boy]

If I trim my motor all the way down it will block my side imaging and I see a reflection of what’s on the right side on the left.  This happens even if I’m not moving.  I don’t think that’s what’s happening in your case.   I think your side imaging is being blocked by air when the left side of the transducer comes out of the water as you increase your speed.  It’s hard to tell from the photo but it might help to lower the transducer a little.

[Woody B]

Are you alone in the boat, or is the person in the passenger side lighter than you?  My boat done that when I was by myself.  The boat would lean to the right, making the left side view not work correctly.  I lowered the transducer and tilted it a little to correct it.  

[Junger]

2 hours ago, Woody B said:

Are you alone in the boat, or is the person in the passenger side lighter than you?  My boat done that when I was by myself.  The boat would lean to the right, making the left side view not work correctly.  I lowered the transducer and tilted it a little to correct it.  

 

My dad is usually with me, but it's a good 80lbs lighter than me. I'm going to try lowering/tilting it down too next time.

[Junger]

On 5/20/2022 at 2:35 PM, Tennessee Boy said:

If I trim my motor all the way down it will block my side imaging and I see a reflection of what’s on the right side on the left.  This happens even if I’m not moving.  I don’t think that’s what’s happening in your case.   I think your side imaging is being blocked by air when the left side of the transducer comes out of the water as you increase your speed.  It’s hard to tell from the photo but it might help to lower the transducer a little.

 

Here are some more pictures on the trailer, placement, angle (used an adjustable level at about 5mph), and the distance from the pad/no strake lines near it.

 

Also today, I hit an electric only lake so I was only using the TM, and hit about 3.3-3.5mph. The motor was trimmed all the way down because my young son was "driving" the boat by using it as a rudder. But, I was getting perfect left side images even with the engine trimmed all the way down. It's gotta be water disturbance from the prop when the big engine is on right?

 

[Tennessee Boy]

I still think the left signal is being blocked by the air pocket that forms behind the transom as you increase your speed.

[Junger]

5 minutes ago, Tennessee Boy said:

I still think the left signal is being blocked by the air pocket that forms behind the transom as you increase your speed.

 

Fixes? Add a transducer to the left side with the Y cable, or move the transducer down the stern closer to the pad?

[Tennessee Boy]

3 minutes ago, Junger said:

 

Fixes? Add a transducer to the left side with the Y cable, or move the transducer down the stern closer to the pad?

The first thing I would try is loosing the screws and lowering the transducer to see how much that helps. That should be easy.   It looks like your transducer is mounted much higher than mine.

[gim]

This is an interesting thread.  I never even thought about the outboard being in the way of the side imaging transducer.