Topic: Hummy in the Salt, need help!

[striper]

This is my first post on this site.
I have monitored this site, for few weeks trying to decide on which side imaging unit to buy.
I chose the 998c si combo because Humminbird uses one transducer, can use the y cable and (2) SI transducer if I had obstruction interference,
no black box etc.

I mounted this unit on my GW-270.
Due to all the nuances in installing the SI transducer, I decided to fabricate an aluminum adjustable transom bracket.
With it I can adjust the height, transducer angle, and the position on the transom without hauling the boat out of the water.
Also less drill holes in the hull.
So far the best spot is in the center between the two motors.
I must say it has performed better than I thought.

The reason I am posting is I believe I have a problem with the side imaging in this unit.
The left side view is more intense than the right side.
Attached are snapshot views mostly in the marina channel. I tried to take the snapshot view of the same area viewing it with
the left side than the right side. 1L-1R, 2L-2R etc.
The wide views also shows the difference in intensity.
Been on the water for three morning trying everthing but without any success.
I spoke to Humminbird yesterday and perform all of her tests but the only conclusion was to send it in for service.

What do you guys think?

attachment=3]

[sonar2000]

Have you tried runnig a bit faster?  maybe 1 to 1.5 MPH.
 
Did you set the unit for salt water?

Is there any kind of keel line directly in front of the transducer?

Have you tried lowering the transducer on your adjustable shaft just a bit more?

Enough questions for now.  let us know. 

Chuck

 

[striper]

I have done all your suggestions.
What do you mean by keel line?

The snapshots do not show the exact intensity difference between the two views.

I'm having trouble posting the images correctly.
First time posting.

[RGecy]

Striper,

Welcome to the forum.  Nice looking install and you did a great job on the transducer mount!  The images look pretty good, but I see what you are saying about a weaker return on the right side.

It looks like the transducer may be tilted a little.  Is the transducer perfectly level side to side or does the boat tilt a little to the starboard when running?  In such shallow water, if its tilted even just a little, the returns will look different.  The images in the deeper water look pretty good and the intensity looks the same or close.

I know in my boat if its just me, mine will tilt to the starboard due to the weight.  I usually carry some scuba gear and keep it on the port side to help balance things out!

Does the pole mount allow you to get the transducer down any further.  Since it is just to the port side of center, you may be getting a little turbulence from the V on the right side and this is weakening the signal.  Maybe!

I really don't think its the unit.  At the very worst, try another transducer and see what happens.

Good luck and let us know if you get it resolved.

Robert

[striper]

Robert,

Thanks for the welcome.

The boat is 27' and has trim tabs, which I adjusted to see if any difference in the view but not much change.
The picture distorts the angle of the bracket, it is straight vertical and also it was taken as a reference.
I have moved the bracket and adjusted it numerous times.

I can and have adjusted the depth of the transducer from above to below the keel with no change in intensity.
I have moved it to either side of the keel line with no change.
Were I have it now I get very little disturbance and can read si bottom over 30 mph.
Looking at the two images attached you do not see the difference?
It is a lot more on the unit screen.
The transducer was my first thought but the Humminbird rep said it could be the unit.

The wider the view the more noticeable the difference in intensity.

[sonar2000]

the keel line I was looking for is the very center of the bottom of the boat.  but it looks like you have adjusted to a lower position.  As Robert indicated it could be the transducer.  Any friends that can loan a transducer.    chuck

[Jolly Roger]

Hm hm hm......

My first thought was like Robert's: Looks to me as if the transducer is tilted down a bit to the right. But if you say it is leveled.... hm hm.

Try disconnecting and reconnecting the transducer cable from the unit. Maybe there's a connection problem.

If that doesn't help, I rather think it's the transducer than the unit.

Greg always advices to try the head unit on someone else' boat. If the unit works fine there, it is a transducer problem. If it acts the same way on the other boat, it is the unit itself.

Regards / Harry

[stillbear]

IMHO looks like the transducer is tilted to the starboard ever so slightly. I agree with
Robert.    Gary 

[striper]

The images posted is with the transducer mounted on the starboard side of the keel.
I made sure and checked a few times that the transducer is horizontal or parallel to the water level. As I stated above , the boat  is equipped with trim tabs and I changed the angle +- with no visible change in intensity.
I would assume if you are in water depths of 100-150' that a slight list could change the return signal, but at 6'-20' the signal intensity should not be as pronounce as I'm seeing.
These imaging were taken on very calm clear waters.
You guys with smaller boats without trim tabs, when you get in  at the helm and the boats lists does your intensity change noticeable.
I wish I could switchout with someone else but Humminbird is non existant in this area. I doubt if there is another unit within 50 miles of me.
I have until tomorrow to return it and get a replacement.
You guys have any other ideas or thoughts?

[RGecy]

The images are not terrible, but I definitely see a slight difference.  If you only have till tomorrow to change it out, then I would take advantage of it. 

Are you returning the transducer as well or are they just swapping out head units?  I would defintiely send the transducer back just in case its the problem!

What freq were the images taken with and does it do this in both 455khz and 800khz?

Robert

[sonar2000]

For the two screens where the speed was 10 mph you could be getting some cavitation on the transducer. 

for the slower speeds it looks pretty good. 

Chuck

[striper]

Went out this morning, in the rain for more testing.
All the previous snapshots were at 455 kHz.
I double checked your all contention that the transducer is tilted to one side.
I tested, your theory, by swinging the bracket like a pendalum approx. 5 deg. each direction but the affects were minimal at best in intensity change as shown in attached photo. The lines are the change in angle.

I also took along a angle level to make sure the boat is not listing and to check plumb of the bracket, all looked fine.
When I change to 800 kHz their is a definite contrast in the two signals.

I appreciate all your help, I'm new to this side imaging but so far it has surpassed my minimal expectation.
It is a great add on to saltwater fishing.
The dealer emailed me a RA# so he is sending me out a new unit so I can swap out the bad part.
Will keep you guys informed.

[Humminbird_Greg]

Striper,
That’s a nice bracket and solution for your Si transducer mounting needs on your boat.  The problem could be in the transducer or the unit.  I think that you have proven it is not the mounting of the transducer here.  The images while drifting rule out any water-air bubble turbulence coming off the hull.  I would have thought that Humminbird would have sent you out a transducer to try instead of sending the unit in as the transducer is the more likely culprit here.  Harry is right: the best way to tell which it is would be to test it on another boat but since that option is not open to you and since you had just today to return it than I think you did the right thing in seeking to return it.  Kudos to your dealer for sending you a unit to troubleshoot with!  Please let us know which part it was that caused this.

Also consider a “how I built it” article on that transducer bracket for this web site.