Incorrect Depth readings from Lowrance

[xIIx]

Hi guys,

I am new to the boating world. I just got a Procraft 192 SC. It's only seen the water twice. Are depth finders known to give incorrect readings? I was in a low channel at Sardis Dam last week. There were "shallow postings" everywhere in that part of the lake. My lowrance started flashing 3.5 and 5.5 feet. So I trimmed her up and creeped across. Then it started showing a depth of 35-45 feet. About 10 seconds later while showing a depth of 35 feet my engine's fine bottomed out on the ground. That's not the 2nd time I've got incorrect depth readings. It will say it's 72 feet deep while i'm at the boat ramp still on the trailer. Any suggestions?

 

[wire2]

Re: Incorrect Depth readings from Lowrance

I've had a couple different ones, they're usually pretty reliable. Where is your transducer mounted? Is the TD cable routed along & close to higher current power wires?

 

[Zero Balance]

Re: Incorrect Depth readings from Lowrance

I had an Eagle and my buddy a Lowrance. Both FF's did this in shallow conditions. I replaced my Eagle with a Humminbird and now I only loose accurate depth under 1' deep. I have a tinny with a 4" draft. I also use the humminbird on my bigger boat. This is one reason I dont care for Lowrance/Eagle units. Look to see if there is a keel depth option. This can give a more accuate reading display.

 

[JB]

Re: Incorrect Depth readings from Lowrance

I guess I have had a dozen Lowrance/Eagle units over the years and don't recall EVER getting unreliable readings when the Xducer is correctly installed and the screen or flasher is correctly read.

 

[Esox]

Re: Incorrect Depth readings from Lowrance

If you don't have a manual for your unit you can get one at the lowrance website. Read through the transducer mounting instructions and check to make sure yours is installed correctly. My guess - like JB - says is it's probably mounted incorrecly. All the sonars I've had from various manufacturers have all been reasonably accurate when they are setup correctly.

 

[gonefishie]

Re: Incorrect Depth readings from Lowrance

My bet is that your unit is an older one and probably have shoot thru hull xducer. Older shoot thru hull does that when you're in water less then 2ft, sometime it will work up to 1.5ft. About being on the ramp, there isn't a single depth finder in the world that won't give you inaccurate reading when there is air under the xducer. My LMS480 will read less then a foot and it's transom mounted. Back when I have an old Humminjunk, whenever I approached shallow water around 2-3ft I became real cautious. The moment that reading went blank or jumped, I shut down and use the trolling motor.

 

[xIIx]

Re: Incorrect Depth readings from Lowrance

I do have the manual. The Lowrance came pre-installed on my dash. I think the Transducer is ran to the back of the boat near the engine mount to the bottom back of my hull.

 

[John_S]

Re: Incorrect Depth readings from Lowrance

If it is a transom mount, it could be as simple as positioning the transducer back down. Most are designed to push up and away if they come in contact with something. They don't drop back down. At extreme angles you can get some very deep readings in shallow water. The puck should be parrellel to the sea/lake bottom.

 

[gregmsr]

Re: Incorrect Depth readings from Lowrance

Does it have a "simulation mode"? Last year I booggered up my prop due to kids playing with settings and found it ( Piranna sp) was in simulation mode. Said I was in 40ft of water at the time of impact. Check settings.
Why the heck does it (mine) have this mode?

 

[xIIx]

Re: Incorrect Depth readings from Lowrance

in fact it does have it. sometimes it flashes up "simulation"

 

[gonefishie]

Re: Incorrect Depth readings from Lowrance

Why the heck does it (mine) have this mode?

For testing purpose! As far as I know, they all have them.

 

[xIIx]

Re: Incorrect Depth readings from Lowrance

i bet mine is in simulation mode LOL ..maybe I should read the manual. I won't be going out anymore this year anyhow.

 

[Barnacle_Bill]

Re: Incorrect Depth readings from Lowrance

I guess I have had a dozen Lowrance/Eagle units over the years and don't recall EVER getting unreliable readings when the Xducer is correctly installed and the screen or flasher is correctly read.

I agree 100% for what it worth. I have a Lowrance on the bow and one on the console. They both will read less than 1 ft.

 

[Boatist]

Re: Incorrect Depth readings from Lowrance

Older units in shallow water you may need to turn the sensitivy way down.
Also if it is a unit with a surface clutter control turn it off in water under 10 feet. If the screen is flashing the digital readout is unrelibable until it stops flashing, however the bottom signal on the screen is usually correct. If the screen is all black then need to turn down the sensitivy.

If you do not know where it was set last may be a good idea to set back to factory defaults and start over. You will need to reset keel ofsets it you had it set before.