Help diagnose depth finder problem

[rocklobster]

Hello,

I have been working with my dealer to fix a depth finder problem. It seems to be an intermittent problem because sometimes it starts to look like a bar graph with vertical blocks. Other times, it looks like it may be ok but it seems to show a lot of red by the waterline which still looks wrong to me. Its a 2017 C28 boat. He also upgraded the software to the latest patch and that didn't help. They also removed the transducer and sanded the surface of the hull where it was mounted. It seems to start failing after it's used for a while.

Here are some pictures.

 

[stwendl]

I could be wrong but the vertical blocks look like the sounder is switching between different depth settings every few seconds. Try to force a settting instead of doing auto in bottom search. Could be caused by the ground or layers of water of different temperature. Just a guess, barring any fault.

 

[rocklobster]

Is it normal to hear the sending unit under the floor clicking/chirping during use when the engine is off and it’s quiet?


Sent from my iPhone using Tapatalk

 

[knotflying]

I never heard mine making any noise.

 

[RichV]

I had sonar transducer problems since purchasing my C28 3 years ago. It improved after the dealer re-positioned it. He said it might have been over a bubble in the fiberglass, but my dealer has been less than reliable and believable with several things. So this spring went it stopped working altogether suddenly while a the dock, I decided to figure it out myself. It's a Airmar P79 which has rotation marks for degrees of deadrise. Setting it at my calculated angle didn't seem to work, so I just rotated it until it did. This weekend I dropped anchor, then measured the rode to verify the depth matched the sonar, which it did. It's finally working consistently, which is a lot less stressful. My screen had looked like yours occasionally but mostly the depth reading would just flash the last known number on and off until it stated to work again.