Hard Bottom?

**gzrglide** · 05-29-2016, 09:14 AM

This past week fishing at Grenada found a couple of areas that caused my 2D sonar to show double bottom like this, no matter how much I backed off on Sensitivity could not get it to stop doing this. We were actually in about 14 feet of water as the transducer I had selected is on the bottom of my trolling motor which was about 2 feet under the surface at the time. Second time it happened, realized that every time we hit this transition, we caught a fish or at least got hits on the poles, so we worked this transition line as much as the wind would let us.

**Hanr3** · 05-29-2016, 09:21 PM

Looks like a thermocline line 13-14' down. and double image at the bottom would be a hard bottom. That red bar would be the hard, and it looks like there is a thin line of sediment on top of it.

**gzrglide** · 05-29-2016, 09:28 PM

Originally Posted by Hanr3

Looks like a thermocline line 13-14' down. and double image at the bottom would be a hard bottom. That red bar would be the hard, and it looks like there is a thin line of sediment on top of it.

I understand what you are saying, but I was in 14 feet of water and the bottom was 12 feet below my transducer on my trolling motor, not in 23 feet of water.

**rnvinc** · 05-29-2016, 10:19 PM

Switchfire Clear can help remove the double echo sometimes ...

But then ... Some guys (like yourself) consciously take advantage of the double echo data being shown to you ...to catch fish ...

I say ... Great job ...

Rickie

**Cane Pole** · 06-05-2016, 10:04 AM

remove double image by turning sensitivity down.

**gzrglide** · 06-06-2016, 12:08 AM

Originally Posted by Cane Pole

remove double image by turning sensitivity down.

Tried that, turned the sensitivity on the 2d sonar, di sonar, and SI sonar all the way down to 1, and turned off my dash unit, the double image remained. I turned the dash unit back on, and switched from the transducer on the trolling motor to the transducer on transom, the double image remained on the bow unit. The dash unit never developed the double image even when I switched the dash unit to the trolling motor mounted transducer. Just seems to be something about this head unit and those two locations on Grenada. I only ran into it in two places on Grenada and have not run into it on any other lake I have been on. As Rickie pointed out above, I did use it to my advantage, I found the interface line between where I was showing double bottom and single bottom and worked that line, that is where we consistently caught fish.

**Cane Pole** · 06-06-2016, 05:01 PM

Take your depth off automatic and select a fixed depth.

I believe the double depth (echo) display is a selectable feature on some head units. Really not a bad thing to have.

I am not familiar with this unit, but too much receiver gain usually is the culprit on any unit.

**gzrglide** · 06-06-2016, 07:14 PM

Originally Posted by Cane Pole

Take your depth off automatic and select a fixed depth.

I believe the double depth (echo) display is a selectable feature on some head units. Really not a bad thing to have.

I am not familiar with this unit, but too much receiver gain usually is the culprit on any unit.

Thanks Cane Pole, will try that next time it happens. It was useful in identifying the interface line and helping to catch fish.

Thread: Hard Bottom?

Thread Tools

Display

Hard Bottom?

Tags for this Thread

Posting Permissions