Depth Display on Garmin and Raymarine Sounders

[Here Be]

There is 13 posts on this subject recently which relate to the depth reading falling off the screen by users of Garmin sounders. I have Raymarine sounder and I am aware of two other owners of 21EC tugs with Raymarine sounders and all of us have the same problem of the depth reading falling off the screen.
My personal view is that the location of the through the hull transducer is wrongly located and as this problem covers two brands of sounders I dont think it is a problem with the sounders.
Could the factory please investigate this dilemma

 

[bbrh842]

I have Raymarine on my R-25.
The display goes to 0.0 when the depth gets below 2 feet.
I don't think it is able to measure less than two feet.

During the first year I experienced an anomally where the depth display would go blank from time to time.
I had to return the chart plotter to Raymarine.
They replaced the Depth Sounder Module under warranty.
That was two years ago.
It has worked fine since then.

 

[Nellie Too]

Ours was set to read from the keel depth so at zero the bottom of the keel is touching the bottom yours may be set the same.
Bob

 

[bbrh842]

Bob,

The "Offset" on my Raymarine is set to zero.
So...it is measuring how much water is below the transducer.
The transducer is about 1 foot below the water line.
When I see 2 feet on the sounder, the water is 3 feet deep, and I still have about 1 foot below the keel.
At this point the depth display goes from 2 feet to zero.
I know that when the display goes from 2 feet to zero, it is time to stop the boat, turn around, and go back the way I came.
Don't ask me how I know this.

Mike

 

[Here Be]

The problem is that the depth reading goes off the screen when the water depth falls below 10 feet

 

[Nellie Too]

Mike,
I just wanted all to know that the depth at which the measurement is taken can be changed, ours is set to the bottom of the keel (2 feet). If yours is set at the waterline then you have another problem. Information is always good thats why I responded.
Bob

 

[gorndorff]

I am a new Tug owner and have a Garmin 541s. My problem is that in shallow water, depth unknown since the sounder quits working and reports 1.6 or 1.8 feet with NO offset input. I'm not aground and am pretty sure I have a foot under me but can't prove it without doing the Mark twain thing and heaving a weight overboard. Now what is really concerning is when I return to deep water, in the channel for example that measured 10 feet or so the only way I can get the depth sounder to read again accurately is to turn off the unit. This problem is not specific to any location so it’s not clutter, weeds or fish, etc causing the incorrect depth reading.
I'm adding a second unit, maybe a hummingbird. My boat is small for a reason, I like going into the bayous around the Tampa bay area and need to have some degree of accuracy in fairly shallow and shoal prone waters. Looking forward to what others can tell me about this issue. I have sent a note to the Garmin folks as well.
George

 

[RProffer]

I was having problems with my sounder. In another post, Paradox suggested changing the Gain, which I did and it fixed my problem. I have since noted on other websites where various sounder problems would get "fixed" by adjusting the Gain. I recommend you try adjusting the gain to see if that fixes your problem.

The following are the directions Paradox gave for changing the Gain on Garmin "I get this frequently, and improve the readout by setting the gain on the depth sounder from automatic to manual then selecting maximum gain - this improves consistency of readings in most conditions.
In the sonar mode, push the menu button, and you will be able to adjust several settings, including the gain. "