Sonar troubleshooting question

[kodiakbound]

Today my depth reading on my Lowrance HDS 5 started flaking out while on step. I've had this unit for 3 years and it has never had this issue. Other than checking connections is there anything else that could be an issue?

Thanks for any input
Kevin

[Music Man]

Anything on the bottom [dent, barnacles]that might cause cavitation bubbles in the beam?

[cod]

Anything on the bottom [dent, barnacles]that might cause cavitation bubbles in the beam?

Yep, or the tranducer angle has changed.

[kodiakbound]

I'll give things a good look over today. Thanks for the tips!

[cormit]

If your transducer is a transom mount ...... it is always possible to hit something in the water that is unseen. Even a slight change in transducer angle can spoil a clean signal.

[Garyak]

Yep, or the tranducer angle has changed.

I have a problem similar to kodiakbound's with my Lowrance LMS 527-CDF transom mount transducer. I lose sonar at only 10 mph but have to drop down under 5 mph to reacquire. The 'ducer is undamaged and clean as is the hull which has a flat bottom...I've adjusted the angle both up and down and find the sweet spot..which isn't sweet at all.. to be where it was initially installed. ???

[tzieli22]

In upgrading my electronics this year I was informed that transducers do go bad. A bit disappointing given you can spend thousands of dollars on them, but then again, not much out there that works for ever. Might want to call lowrance to see how you might test it. That is as long as nothing has changed on your hull to give you turbulence.

[kodiakbound]

Thanks for all the replies. I didn't find anything that jumped out at me. It didn't look like the angle had changed or the transducer had been struck or moved any. Nothing on the bottom that should cause any turbulance. I did make a small angle change but have not had a chance to test on the water yet, kids have been keeping me busy!!!

[cod]

Transducer angle doesn't have to change very much at all to lose signal. The fact u have signal and then lose it as u speed up leads one to believe that u are either getting cavitation bubbles under it or when on step your hull angle ( and thus your transducer angle) has changed enough to lose signal. Generally when accelerating your hull angle will become steeper. When on step it will flatten a bit. It may be the 'flattening' of the angle that is causing signal lose. Try adjusting just enough to compensate for it.
Since u do get signal, I would have to believe nothing's wrong w the sonar.
Let us know what u find.

[Garyak]

I agree, cod...when participating, the sonar seems to work fine. I went ahead and adjusted it up a notch. As I recall that really messed things up while at rest but I'll give it a shot. I also have a paddle wheel down there. It is 3 1/4 inches from the edge of the 'ducer to the edge of the paddle wheel. Do you think that could be close enough to cause a problem?

[cod]

Absolutely. Is that a 'new' addition? If so, almost guarantee that's your prob.

[Garyak]

Absolutely. Is that a 'new' addition? If so, almost guarantee that's your prob.

I installed it at the same time as the 'ducer so I've had the issue from day 1. I have exactly 2 inches I could move it outboard before the hull begins to upsweep...and even further if mounting it on the upsweep wouldn't hurt anything...but it would likely be out of the water during turns.

[DRIFTER_016]

Mine is closer than yours and I get readings at full speed so the paddle wheel is not your issue.



If you've had the issue from day one it is most likely one of two things. A defective/weak transducer or the location of the transducer on the back of the boat.
Check under the boat for any strakes or chines anywhere close to the path the water takes passing under the hull.
Most likely culprit is air travelling along the bottom of the hull. Moving the transducer further inboard may very likely rectify the issue.

[BrownBear]

...started flaking....

Something just wiggled my memory gland, Kevin....

Maybe too basic, but did you use dieiectric silicone grease on the plug between the unit and the transducer wire? I wasn't doing that a few years back and developed symptoms similar to yours- complete blackout on step. Cleaned the terminals and added the dielectric goop, and no problems since.

[cod]

I installed it at the same time as the 'ducer so I've had the issue from day 1. I have exactly 2 inches I could move it outboard before the hull begins to upsweep...and even further if mounting it on the upsweep wouldn't hurt anything...but it would likely be out of the water during turns.


In looking at your pics.... Probably NOT the problem. I thought the wheel would be bigger than what your pic shows. Don't think that little thing could cause enough turbulence.

looking at your pics.... Probably NOT the problem. I thought the wheel would be bigger than what your pic shows. Don't think that little thing could cause enough turbulence.