Shallow Water Sonar

Discussion in 'Fishing Electronics Review' started by mhbomber, Feb 16, 2009.

  1. mhbomber

    mhbomber New Member

    Messages:
    268
    State:
    Wilmington
    I have been told that sonar will not mark fish or structure well in less than 20 feet of water regardless of how nice the unit is. What are you guys thoughts on this? One lake that I fish in a lot is a steam plant lake with average depths of around 10 feet. Will it only be able to show me depth or can I fine tune it to show other fish/structure? Right now I am running a Lowrance X-96.

    Thanks for the input!
     
  2. Bill in SC

    Bill in SC New Member

    Messages:
    4,451
    State:
    South Caro
    Most of my river fishin' is between 0 and 30 feet. I frequently mark fish on my unit in 20 feet or less water. Since I often catch the fish that I mark on the unit, I'd say that it works pretty good. When the depth gets below 10 feet, the unit does not seem to be as efficient. I have a cheap Eagle 320 as a secondary unit, and an Eagle 502c as my primary unit. Both units consistently mark fish well in the 10 to 20 foot depth range.

    Bill in SC
     

  3. Grimpuppy

    Grimpuppy New Member

    Messages:
    3,556
    State:
    Concordia, KS
    I don't have any trouble with structure under 10' of water. It doesn't have trouble with fish either, IF you can get on top of them. Problem with fish is, your sonar is emitted in a cone pattern. The deeper the water the bigger the cone is when it gets to the bottom. The rule of thumb is that your sonar sees a circle approx the same diameter as the depth of the water. So if you are in 30 feet of water, your sonar is reading a 30' circle of the bottom. You are also 30' above the fish and not spooking them. Now drop down to 7' of water. Now you are only seeing a 7' diameter circle of the bottom. Basically you are seeing what is right under the boat only. So if you have your big motor running, chances are you will scare fish out of the way and you sonar will never see them. I hardly ever mark fish in shallow water with the big motor on. I can mark them occasionally with the trolling motor. I see them no problem when I am drifting with the wind and drift over top of them. There are lots of times I drift over them and 15 seconds later I get a fish on. Don't know if they are the same ones but when drifting if I see them on the screen, I get ready.