Any way of testing depth sounder out of water?

[CZSteve]

We have a an older Lowrance X22A fish finder (1997). Currently have the boat on the trailer for maintenance / cleaning. Is there any way of testing this unit before putting back into the slip?
It powers up fine and shows .5 ft on the display. My brother said it seemed to be erratic the last time he was out. The sounder and line do not show any signs of damage.

If we do have to replace is it worthwhile going with a GPS unit?
We use the boat on inland lakes; same lake on a regular basis. Also have a smart phone with the Navionics app. Any strong reasons for a unit with GPS over using the phone? Obviously convenience would be better; just be frugal with funds whenever possible.

[r.j.dawg]

My fishfinder occasionally gives me strange readings. It's normally caused by a dirty transponder. Here are a couple of hints from my owners manual. I would get a plastic bag (ziplock) full of water and tie it around your transponder. They have to be submerged in water to work.

1. Occasionally the “eye“ of your transducer may become dirty from storage or from contact withoils present in boats or marina environments. (Oil will cause the “eye” to lose the intimatecontact with the water which is necessary for efficient operation.) The “eye” may be cleanedwith liquid detergent.

2. Improper installation of the transducer can alter the efficiency and accuracy of the entiresystem.

3. If your boat of transducer is out of the water for a period of time, it may take a short period oftime for the transducer to become thoroughly “wetted” when returned to the water. Also, reentrymay cause turbulence, which will create air bubbles in the “eye” of the transducer. The bubbles will disappear in a short time or can be removed by rubbing the transducer “eye” withyour fingers while the transducer is in the water.

4. If your instrument should fail to function, be sure to check all the electrical connections beforeremoving the transducer or calling a serviceman.

5. Inspect your transducer cable and make sure that it has not been cut or damaged to the pointwhere it will affect the performance of the transducer. A slight nick or cut, exposing the outercable, can be repaired by wrapping with electrical tape. A transducer can be damaged if theinner cable and outer cable are allowed to make contact. Such a problem can sometimes becorrected by properly splicing the coaxial cable. This should only be attempted by a qualifiedservice technician.

6. If your LCR is not working properly and you suspect the problem might be in your transducer,we would recommend you borrow a unit from a friend and try it on your boat. If the symptomsare the same, you can almost be certain that the problem is in the transducer.

[Monterey10]

The most important "testing" is done in the water, to see if the transducer is picking up air bubbles from under the hull, at speed. If the transducer is correctly placed, it will read up to about 20 mph.

Another test is to check if the transducer is pointing straight down. I use a fishing rod with a large flasher and weight. I drop the flasher down either side of the boat and watch when it shows on the sounder's screen. This gives me an idea as to which way the transducer is looking. I do this on narrow band sounders, that are looking down into deeper water. Just a fraction of angle change to the transducer will move the beam quite a bit.

The last one I checked showed the flasher on the starboard side of the boat, not the port. I stood center ship on a calm day to keep the boat level.

transducer2.gif

[Outsider]

If the transducer is correctly placed, it will read up to about 20 mph.

If the best mine would do is 20 mph, it would be on Ebay. If the transducer is properly placed, it should function at speeds well above 20 in most applications ...

[dingbat]

My fishfinder occasionally gives me strange readings. It's normally caused by a dirty transponder. Here are a couple of hints from my owners manual

1. Occasionally the “eye“ of your transducer may become dirty from storage or from contact withoils present in boats or marina environments. (Oil will cause the “eye” to lose the intimatecontact with the water which is necessary for efficient operation.) The “eye” may be cleanedwith liquid detergent.

My “eye” is submerged in a tank of oil so it’s not in intimate contact with the water. Should I be concerned?

3. If your boat of transducer is out of the water for a period of time, it may take a short period oftime for the transducer to become thoroughly “wetted” when returned to the water.

How long does it have to be out of the water before I have to let my “eye” soak before it can be used again?

6. If your LCR is not working properly.........

What is an LCR?

[joebob14]

.5 ft dosnt sound right to me. air is less dense then water so if the boat is out of the water and you are reading .5 ft you would be about a quarter inch off the ground. I have tried it with many boats and with the boat on a trailor they read about 120 ft. If it is working I would think the transducer would be covered in a pretty thick layer of crud to get a reading of .5 ft.

[dingbat]

.5 ft dosnt sound right to me. air is less dense then water so if the boat is out of the water and you are reading .5 ft you would be about a quarter inch off the ground. I have tried it with many boats and with the boat on a trailor they read about 120 ft. If it is working I would think the transducer would be covered in a pretty thick layer of crud to get a reading of .5 ft.

Sound propagates thru water 4.3 times faster than air. If the transducer is 2' off the ground so you should read roughly 8.5' deep.

Edit: quoted deleted content - QC