Interference Or Transducer Location....?

[southtexasbassin]

Im getting interference from my outboard I believe.  I got rid of interference from the trolling motor by installing a ferrite ring that humminbird sent me.  My question is after looking at the type of interference I have, I am realizing it could be the location of my transducer.  Dealer said that where they install them all the time with no problem.   I am posting pics of the transducer placement and the interference I am getting on the dash mount Hummindird 998.  Transducer is mounted on jack plate.   It usually appears on the screen when I accelerate.  Any suggestions on what it might be?  

 

[jhoffman]

Prop wash, id try moving it as far left or right as possible.

Can you take a strait on pic

[Wayne P.]

Propwash is impossible with your installation unless you have the motor in reverse.

What you have is no water on the transducer when you are getting the black streaks.

That is caused by going too fast with the mount location you have.

[Koofy Smacker]

I cant tell from the picture but is the transducer actually above the bottom of the boat? Meaning take a ruler, put it on the bottom of the boat and is the transducer above or below it. I cant tell. If its doing that when you accelerate then there is probably no water there whatsoever. Ive had mine mounted half above and half below the bottom of the boat. This way any water coming under the boat comes in contact with it.

[Wayne P.]

I cant tell from the picture but is the transducer actually above the bottom of the boat? Meaning take a ruler, put it on the bottom of the boat and is the transducer above or below it. I cant tell. If its doing that when you accelerate then there is probably no water there whatsoever. Ive had mine mounted half above and half below the bottom of the boat. This way any water coming under the boat comes in contact with it.

I cant tell from the picture but is the transducer actually above the bottom of the boat? Meaning take a ruler, put it on the bottom of the boat and is the transducer above or below it. I cant tell. If its doing that when you accelerate then there is probably no water there whatsoever. Ive had mine mounted half above and half below the bottom of the boat. This way any water coming under the boat comes in contact with it.

He stated it was on his jackplate. Do you know what that is?

[Koofy Smacker]

He stated it was on his jackplate. Do you know what that is?

Yes I do Wayne. Thanks for asking. I didn't realize he stated that.

 

That's what happening then is when accelerating there is a void of water around the transducer creating what your seeing. Long story short unless your fine going slow and keeping the back of the boat under the water you'll have to remount at a different point on the hull.

[Traveler2586]

I cant tell from the picture but is the transducer actually above the bottom of the boat? Meaning take a ruler, put it on the bottom of the boat and is the transducer above or below it. I cant tell. If its doing that when you accelerate then there is probably no water there whatsoever. Ive had mine mounted half above and half below the bottom of the boat. This way any water coming under the boat comes in contact with it.

 

X2, you want the trans in clean water flow from under the boat.

 

I'm not sure what your trying to say here about "half above & half below"

 

 

 

Propwash is impossible with your installation unless you have the motor in reverse.

What you have is no water on the transducer when you are getting the black streaks.

That is caused by going too fast with the mount location you have.

 

X2, Without a better photo I'll go with Wayne's assessment.

 

Your installation may only be off by an inch or so too high, but that's all it takes to get into the area of air turbulence from the transom.  Do the ruler test to see where you are and adjust accordingly.

[Koofy Smacker]

To clarify, if the transducer is lying flat, the top half should be above the hull and the bottom half below. Basically you dont want the entire transducer above the bottom of the hull to avoid the problem he is having and you dont want it completely below because it disrupts the water flow around it and can cause issues should a stick or anything hit it at speed

[Traveler2586]

To clarify, if the transducer is lying flat, the top half should be above the hull and the bottom half below. Basically you dont want the entire transducer above the bottom of the hull to avoid the problem he is having and you dont want it completely below because it disrupts the water flow around it and can cause issues should a stick or anything hit it at speed

 

OK, I'm with you now, thanks.

 

BTW, what is the top speed for side-scan operation,, 25 - 35 ??   I haven't seen any spec's on that subject.

[Wayne P.]

OK, I'm with you now, thanks.

 

BTW, what is the top speed for side-scan operation,, 25 - 35 ??   I haven't seen any spec's on that subject.

Top speed is about 12mph.

Best images 0-6 when installed to do so and adjusted properly. The slower the better.

The thin imaging pulse has to be on a subject as the screen is scrolling so it can be recorded.

[southtexasbassin]

I tried slowing down a bit and was able to get some awesome pics.  I was the speed!!!    I am getting about 3-4 wiggle lines on the top of the down imaging screen.  I will post some images when I get them.  Thanks for everything guys!

[Wayne P.]

I tried slowing down a bit and was able to get some awesome pics.  I was the speed!!!    I am getting about 3-4 wiggle lines on the top of the down imaging screen.  I will post some images when I get them.  Thanks for everything guys!

Do you have a holeshot plate on you jack plate?

Those lines are on SI also. You will see them on the left side of the center line if you set the SI range to less than 50 feet.

[southtexasbassin]

I do not have a holeshot plate.  Correct the lines are also on the SI screen as well.  Whats the cause?  Attached are a different angle of the the transducer.  

[Downeaster2010]

What you have is actually air/bubbles coming under the hull giving you this reading.  Lower the transducer

1/2 inch, and tilt it forward to catch more water, and you should be good.

[Comfortably Numb]

Could the bracket being backwards cause bubbles?

[jhoffman]

What you have is actually air/bubbles coming under the hull giving you this reading.  Lower the transducer

1/2 inch, and tilt it forward to catch more water, and you should be good.

 

No doubt thats WAY to high and basically what I was referring too when I said prop wash. Sorry that I dont know the "technical term"

[Wayne P.]

I do not have a holeshot plate.  Correct the lines are also on the SI screen as well.  Whats the cause?  Attached are a different angle of the the transducer.  

You are getting echos from the inside of the left side of the jackplate. A holeshot plate will prevent it if you find those lines objectionable

[Downeaster2010]

That is a very poor mounting position.  Looks good that is all.  I have a better plan for you.

 

Where your transducer is will never ever give you a good reading.  Look at it this way, when to boat is on plane your transducer

is 2 to 3 inches out of the water.  It needs to be mounted below that.   When on plane the only part of the boat that is in the

water is the part where the drain plug is and your intakes for the livewells.  To make it simple you can try in this case just

setting the ducer inside the hull flush against the bottom just forward of the drain plug. It must be located on that lowest part

of your hull.  For a test:  Put a little water in the boat  and place the ducer just forward of the drain plug.  No mount or anything.

Just lay it bottom down and add some water inside the hull.   It should read good.  If so open your drain plug and dry out the

area and you can get some epoxy and mount in that location inside unexposed to damage.  You have to coat the bottom of the

ducer real good with epoxy and work it a bit when you press it against the inside of your hull.  You will see a dramatic

improvement.  The simple two part epoxy you get from Walmart will work fine.

 

The epoxy on the transducer mounted to the inside of your hull acts as a direct connection to the water outside.  A lot of

people think that a transducer cannot be mounted inside an aluminum boat, but if this method is tried they most likely will

find it works quite well.  Fiberglass works good.

[Traveler2586]

That is a very poor mounting position.  Looks good that is all.  I have a better plan for you.

 

Where your transducer is will never ever give you a good reading.  Look at it this way, when to boat is on plane your transducer

is 2 to 3 inches out of the water.  It needs to be mounted below that.   When on plane the only part of the boat that is in the

water is the part where the drain plug is and your intakes for the livewells.  To make it simple you can try in this case just

setting the ducer inside the hull flush against the bottom just forward of the drain plug. It must be located on that lowest part

of your hull.  For a test:  Put a little water in the boat  and place the ducer just forward of the drain plug.  No mount or anything.

Just lay it bottom down and add some water inside the hull.   It should read good.  If so open your drain plug and dry out the

area and you can get some epoxy and mount in that location inside unexposed to damage.  You have to coat the bottom of the

ducer real good with epoxy and work it a bit when you press it against the inside of your hull.  You will see a dramatic

improvement.  The simple two part epoxy you get from Walmart will work fine.

 

The epoxy on the transducer mounted to the inside of your hull acts as a direct connection to the water outside.  A lot of

people think that a transducer cannot be mounted inside an aluminum boat, but if this method is tried they most likely will

find it works quite well.  Fiberglass works good.

 

Can Side-Imaging work shooting through the hull???   I think its been said that SI is only good at slow speeds, not while on plain.

[southtexasbassin]

That is a very poor mounting position.  Looks good that is all.  I have a better plan for you.

 

Where your transducer is will never ever give you a good reading.  Look at it this way, when to boat is on plane your transducer

is 2 to 3 inches out of the water.  It needs to be mounted below that.   When on plane the only part of the boat that is in the

water is the part where the drain plug is and your intakes for the livewells.  To make it simple you can try in this case just

setting the ducer inside the hull flush against the bottom just forward of the drain plug. It must be located on that lowest part

of your hull.  For a test:  Put a little water in the boat  and place the ducer just forward of the drain plug.  No mount or anything.

Just lay it bottom down and add some water inside the hull.   It should read good.  If so open your drain plug and dry out the

area and you can get some epoxy and mount in that location inside unexposed to damage.  You have to coat the bottom of the

ducer real good with epoxy and work it a bit when you press it against the inside of your hull.  You will see a dramatic

improvement.  The simple two part epoxy you get from Walmart will work fine.

 

The epoxy on the transducer mounted to the inside of your hull acts as a direct connection to the water outside.  A lot of

people think that a transducer cannot be mounted inside an aluminum boat, but if this method is tried they most likely will

find it works quite well.  Fiberglass works good.

I have a shoot thru hull already epoxied inside the hull. The SI ducer I'm going to keep it on the jack plate. Go an buy a transducer saver and add the spacer to it. Thanks for all the recommendations.

[Wayne P.]

Can Side-Imaging work shooting through the hull???   I think its been said that SI is only good at slow speeds, not while on plain.

I have a shoot thru hull already epoxied inside the hull. The SI ducer I'm going to keep it on the jack plate. Go an buy a transducer saver and add the spacer to it. Thanks for all the recommendations.

For those that do not know, your setup is typical for high performance pad hull bass boats.

I am at Lake Fork this week and every set up for Humminbird SI and Lowrance SS is the similar to yours.

The boat I am fishing in has his SI transducer in the center of his hole shot plate. He is using the Y cable and shoot thru 2D transducer. It is a Triton.

[Wayne P.]

Can Side-Imaging work shooting through the hull???   I think its been said that SI is only good at slow speeds, not while on plain.

No the SI transducer has to be on the exterior. So does the SS transducer.

[scrutch]

You are getting echos from the inside of the left side of the jackplate. A holeshot plate will prevent it if you find those lines objectionable

Wayne, wouldn't he need to re-mount the ducer to the bottom of the holeshot plate? As I understand it from looking at this photo, the plate covers the entire bottom of the jack plate. If a re-mount is necessary, wouldn't an overall better location for the ducer be down on the step to the right or left of the drain plug? That is the only location that has "clean water" to shoot through. It seems to me that turbulence at any speed other than a crawl is the culprit here. I understand that many of the boats you are seeing are using the jack plate mounting location. How are they eliminating the interference generated by the boat when moving at non-trolling motor speeds?