Topic: Transducer Location Help

[ctsalt12]

Hi All,

New poster here.  There's a wealth of knowledge on here and I'm hoping I can get a bit of help.

I have a Helix 7 SI /GPS.  Installed September of last year.  Really have not had good performance from SI particularly, and at high speeds the readings for DI are not good either.  It's used in saltwater.  I've attached 2 screenshots, a side profile, and a rear view.  The ducer is mounted about 22-23+ inches from the center of the engine.  I think my performance issues are partially because of mounting location.  I moved it far from the engine when I mounted it thinking it would give me a better reading with less vibration and prop interference, but I think that was a bad assumption.  I've learned here prop interference is really only an issue with inboards where the prop is ahead of the ducer.

Symptoms:
1. General lack of clarity on SI.  Nowhere near its potential.  I think I may have some blocked sightline by my engine on the left side too, but not 100% on this.  As you can see from my side profile pic, it's close to the engine. 
2.  Loss of depth at high speed, and roostertail. 
3. Random Wildly fluctuating incorrect depth readings at times. Not always at high speed either.

So I think there are a few things wrong. 

1. For SI-I think I can benefit from moving the ducer a lot closer to the engine, 13inches or less from center of engine.  This will help with the engine interference with SI beams because as you can see I have a V Hull, so the closer to the centerline I go, the lower the ducer goes.  The lower the ducer is, the less surface area of the engine lower unit there is to interfere.  Does this make sense?

Another question.  Do SI beams shoot directly down from the ducer, or down and out to the stern?

2. I think I need to have the 'ducer higher up on my mounting bracket, so the when on plane the 'ducer is surfing more than it is plowing through the water.  The roostertail can't be a good thing, and my ducer is well underwater while on plane.
3.  This is a dumb one, but I didn't use transducer paint so there was a teeny bit of growth at the end of the season which I think led to the inconsistent readings.  I need to clean and paint it this year.

What am I missing?  Any thoughts on my current location?

[fishreed]

Good side scanning readings do NOT happen when the boat is on high speed plane and that was by design. Don't think for a minuyte you are going to get good SI readings when you boat is on plane.    The best readings for SI is when you are going at troll speed. If you want high speed readings , get a dual beam transducer cord and a high speed transom mounted 83/200Khz transducer. What kind of SI/DI are you getting when you are at troll speed less than 3mph? Your  location looks fine to me, I would clean off the transducer bottom.  You should NEVER paint a transducer either.

[ctsalt12]

Thanks fishreed.

I understand I shouldn't expect good high speed readings.  The issue is at low speed the detail stinks, particularly for SI.  DI is not bad.  I think I am definitely getting some blockage by the engine on the left side as well.  I also think it may be due to misalignment horizontally.  The angle looks okay in  my picture, but in the water I feel the bow is up higher, but I'm really not sure.  Will have to adjust in the water.  I'm driving over reefs, wrecks etc., and I can certainly see a rise in depth, but I'm not getting the rich imaging.  No screenshots now as I'm out of the water, but once I'm in I'll send that.

Really no transducer paint for saltwater?  There is specific ducer paint that seems to be commonly used. 

[Bob B]

Here's a good trick for leveling the transducer front to back.....Just make sure the level and the coins are in the same place on the water as on the trailer.

https://www.youtube.com/watch?v=JuYsmJRc_fE

The compact transducer may be part of the reason for not getting as sharp of images as you see from others.  The longer elements in the HDSI transducer will give sharper images.
I couldn't tell from the picture....do you have the rubber filler piece on the transducer ..... it will somewhat help with the rooster tail.

[ctsalt12]

Here's a good trick for leveling the transducer front to back.....Just make sure the level and the coins are in the same place on the water as on the trailer.

https://www.youtube.com/watch?v=JuYsmJRc_fE

The compact transducer may be part of the reason for not getting as sharp of images as you see from others.  The longer elements in the HDSI transducer will give sharper images.
I couldn't tell from the picture....do you have the rubber filler piece on the transducer ..... it will somewhat help with the rooster tail.

Wow, that is a great trick,  Thanks Bob.  I do have the filler piece on.  I assume I just need to raise it up a bit.

[fishreed]

Here's a good trick for leveling the transducer front to back.....Just make sure the level and the coins are in the same place on the water as on the trailer.

https://www.youtube.com/watch?v=JuYsmJRc_fE

The compact transducer may be part of the reason for not getting as sharp of images as you see from others.  The longer elements in the HDSI transducer will give sharper images.
I couldn't tell from the picture....do you have the rubber filler piece on the transducer ..... it will somewhat help with the rooster tail.

I agree with Bob . I have BOTH  the  compact SI and the HDSI transducers ....The 455MHZ on HDSI gives a much better reading as compared to the 455MHZ on the compact Transducer. As a side note, I wasn't much impressed with the 800MHZ. that being said, I would recommend the HDSI transducer but just for the better 455MHZ pizos. this year I am going to run both transducers at 455MHZ with one on my 899SI and the other on my 1199SI so see exactly what the difference is.