Erratic Indications From Depth Sounder

[Alecadi]

So far the depth sounder (Raytheon Tridata S60) indications were correct. Even I calibrated it with the lead line.
Since a little while the depth is acting starngely..
Start during a couple of hours or little more to have the good indications and then after that start giving erratic indications always more than 3 times the real depth.. sometimes after a while getting back to correct indications
Sometimes not at all.

Any idea?
And no, I don't drink and drive...

[Alecadi]

Originally Posted by Alecadi

So far the depth sounder (Raytheon Tridata S60) indications were correct. Even I calibrated it with the lead line.
Since a little while the depth is acting starngely..
Start during a couple of hours or little more to have the good indications and then after that start giving erratic indications always more than 3 times the real depth.. sometimes after a while getting back to correct indications
Sometimes not at all.

Any idea?
And no, I don't drink and drive...

I WOULD LIKE TO PRECISE SOMETHING: I didn't say EROTIC I said ERRATIC:meaning Lacking consistency, regularity, or uniformity.
If my depth sounder was having erotic indications I would be quite happy (more over at my age!) and I would not complain or look for advices...

[cabo_sailor]

If your depth oscillation is occurring while in a busy channel or while having power boats zip past, you may just be seeing the results of their prop cavitation. When they froth up the water a lot of air bubbles are being generated and screw up your depth finder's readings.

I offer this as a suggestion but it does not quite match your symptoms. Usually all the cavitation froth will cause your depth readings to show shallow not deep. It's possible that you have a bad cable or a bad transducer. Perhaps contacting the manufacturer would be in order.

Rich

[Alecadi]

Originally Posted by cabo_sailor

If your depth oscillation is occurring while in a busy channel or while having power boats zip past, you may just be seeing the results of their prop cavitation. When they froth up the water a lot of air bubbles are being generated and screw up your depth finder's readings.

I offer this as a suggestion but it does not quite match your symptoms. Usually all the cavitation froth will cause your depth readings to show shallow not deep. It's possible that you have a bad cable or a bad transducer. Perhaps contacting the manufacturer would be in order.

Rich

Thank you Cabosailor.
I thought about cavitation or even parallax error due to heeling but those (normally) don't last. When cavitation, or heeling, is finished the reading should go back to normal.
Here the wrong indications are staying on a while. Sometimes disappear without any changes in the circumstances or are there for a long time.

[Alecadi]

No more ideas?
I've found nothing on the owner's manual either...

[Catamount]

The depth sounder that is part of my sailing instrument system gives erratic readings exactly like those that you describe when I turn on my separate fishfinder, which has it's own transducer but must be operating on the same frequency.

Could you have a fishfinder or another depth sounder operating at the same time as your erratic depth sounder?

edit: some multifunction display systems could include a fishfinder/sounder function, do you have one of those?

[Alecadi]

Originally Posted by Catamount

The depth sounder that is part of my sailing instrument system gives erratic readings exactly like those that you describe when I turn on my separate fishfinder, which has it's own transducer but must be operating on the same frequency.

Could you have a fishfinder or another depth sounder operating at the same time as your erratic depth sounder?

edit: some multifunction display systems could include a fishfinder/sounder function, do you have one of those?

Nope: only one depth sounder.

[cabo_sailor]

I'm leaning towards it being a faulty transducer. Your depth gauge is just responding to whatever voltage is being sent by the transducer. I don't know how often this occurs but if it is fairly often the next time I had some time, while tied up in the slip, I would turn the depth finder on, prepare a small tumbler of "ol' thought provoker" and watch the depthfinder. If it starts fluctuating to a significant degree, I'd say your transducer is shot.

Rich

[Alecadi]

Originally Posted by cabo_sailor

I'm leaning towards it being a faulty transducer. Your depth gauge is just responding to whatever voltage is being sent by the transducer. I don't know how often this occurs but if it is fairly often the next time I had some time, while tied up in the slip, I would turn the depth finder on, prepare a small tumbler of "ol' thought provoker" and watch the depthfinder. If it starts fluctuating to a significant degree, I'd say your transducer is shot.

Rich

The part about "a small tumbler of "ol' thought provoker" " seems VERY interesting:
1- why small tumbler?
2- Do you have any recipe to share for that stuff???

and I think I'll be ready for the transducer watch ...

[cabo_sailor]

Well Alecadi,

After reading my post, I was just about to edit it to read "a small tumbler of ol' thought provoker or as needed until the symptoms occur, provided you can still read the depth gauge" but you beat me to it.

What made me think of the transducer (not ol' thought provoker) was that a friend has a new depth finder and it was giving off strange readings at the dock. He called the rep, he came down and found the voltages off the transducer were all over the place. He got a new transducer, under warranty, plugged it in and spent an hour or more checking voltages. The new one works fine.

Rich

Oh, yes my recipe is to take a Tervis tumbler, add ice, and then a copious quantity of your favorite thought provoker. Since you are on watch for the depthfinder you do not want to be forced away from your station at frequent intervals to re-fill. You might miss something. Of course this procedure does put an outer limit on your time on watch. Such are the dangers.

Rich

[four winds]

Consider this, only if this is a newly installed device. Within the first couple of months of service any new circuit board can reveal a manufacturing defect at the component level. For example, a cold solder joint on the board or similar defect inside an integrated circuit chip.

The reason I mention this is that fact that the error occurs after operating for about two hours. Heat buildup on the board can trigger the condition, and after cooling off it fixes itself.

If it's new, and consistently faults after two hours, every time, then sea conditions are less likely the cause and the fault likely lies in the unit or transducer itself.

If it's not new, ignore this post.

[Alecadi]

Originally Posted by four winds

Consider this, only if this is a newly installed device. Within the first couple of months of service any new circuit board can reveal a manufacturing defect at the component level. For example, a cold solder joint on the board or similar defect inside an integrated circuit chip.

The reason I mention this is that fact that the error occurs after operating for about two hours. Heat buildup on the board can trigger the condition, and after cooling off it fixes itself.

If it's new, and consistently faults after two hours, every time, then sea conditions are less likely the cause and the fault likely lies in the unit or transducer itself.

If it's not new, ignore this post.

The depth and transducer are not new.
But the problem is new

[Alecadi]

Originally Posted by cabo_sailor

Well Alecadi,

After reading my post, I was just about to edit it to read "a small tumbler of ol' thought provoker or as needed until the symptoms occur, provided you can still read the depth gauge" but you beat me to it.

What made me think of the transducer (not ol' thought provoker) was that a friend has a new depth finder and it was giving off strange readings at the dock. He called the rep, he came down and found the voltages off the transducer were all over the place. He got a new transducer, under warranty, plugged it in and spent an hour or more checking voltages. The new one works fine.

Rich

Oh, yes my recipe is to take a Tervis tumbler, add ice, and then a copious quantity of your favorite thought provoker. Since you are on watch for the depthfinder you do not want to be forced away from your station at frequent intervals to re-fill. You might miss something. Of course this procedure does put an outer limit on your time on watch. Such are the dangers.

Rich

Thanks
You indicated new transducer. It's not the case here, installation has some age already

[Alecadi]

All this is pointing to the transducer and probably to the electric connections.
No?
I would better check the electric connections then as soon as possible (Some crawling to do .. my back is already complaining!)

[four winds]

Yes it does. Corrosion at a connection serves to add resistance to current flow. It also causes heat buildup, however slight at the current level in a transducer wire. This added resistance could easily alter the reading at the gauge. Since measuring resistance in the transducer is how it works. Granted that is an over-simplification.

Cleaning connections would be a good first step.