finding hard to soft bottom on lawrance?

[mnhunter79]

I have two lawrances on my boat, ( x-96 and the other one is a big screen gray scale not color) I know pretty much everything about them and how they work except how to determine the bottom. How do you tell if its mud, sand, gravel?

[fasternu]

I am not positive, but I beleive that the more solid the bottom, the better return. Therefore a gray would be more mud/sand while rocks/gravel would be a darker line (black). I've only had mine 2 weeks, so I could be wrong, I'm just playing with it and getting used to it.

[BobT]

I believe you are pretty much correct. I configure my gray-scale screen using grayline and contrast adjustments so that a hard bottom (sand or gravel) will return a rather distinct thin black bottom line with a lighter grayline below. The lighter the grayline the harder the bottom probably is. The softer the bottom is the thicker the bottom line appears and the darker the grayline below gets. Very soft bottom shows almost no grayline at all but pretty much all black.

Bob

[Farley]

Correct me if I'm wrong but I've also heard that when your depth finder shows 2 bottoms, it usually means hard bottom.

[mnhunter79]

iv'e seen that too. just never knew why or what it was.

[Revermann]

If you see two bottoms it is called a double echo, and it does mean you are on a hard bottom.

[mnhunter79]

Ok thanks. So the fine black line with light grey under that indicates hard bottom and vise versa ?

[Surface Tension]

It depends on your gain setting. Turn up the gain and it'll look like hard bottom. If you know your sounder well and how it prints bottom at all gain levels and at various depths then you can get an indication of bottom density. More often then not you'll compare readings from soft to hard bottom at the same gain level and depth. Then you'll know for sure what the bottom density is. So in a nutshell you can't turn the sounder on and know instantly the bottom density.

Since we're on the subject you might ask then why and how can you tell bottom density this a flasher on ice without hole hopping and comparing those bottom density readings from different locations?

A flasher is a bit simpler in that there is no gray scale or reverse gray scale. Turn the gain up and the bottom marked as red will become thicker. After some hands on experience with your flasher you'll know what soft bottom looks like at a certain depth and gain level. You'll also compare how that favorite jig is printed at a certain depth and gain level. Instant gain adjustment from a twist knob helps you fine tune your interpretation as well. If you have weeds below you can use that as part of or comparison.

So with any sounder it takes time using it to fall back on the stored information in the memory banks to interpret what your seeing.