Need help understanding fish finder

Hello, I have a Humminbird Pirana 210 max with a single 20* cone. It's my first depth finder and I have a few questions. Usally I fish in water 10' to 15' deep ; how much bottom am I seeing ? The screen scroll as I move, fast or slow , and sitting still it scrolls the same; how do I know when an image on the screen is under the boat ? If I'm anchord and the screen scrolls on a loop and I see fish go by and the same structure over and over what am I seeing ? When trolling and I see a drop off I stop and anchor then the drop off is gone , like I over shot it. Any help or advice would be great. :confused: :confused: :confused: :confused: -Thanks

I dont have that particular unit but I'll try to explain a few things. First off, what you see first appearing on the screen is actual real-time structure/fish. As it scrolls across the screen you are seeing what you have ran across, be it 5,10, or 15 feet behind you, depending on your boat speed. You mentioned setting up on a dropoff...without a unit that supports maps,. all you can do is look for the contour change and drop a bouy on the dropoff after you've determined exactly where it is after easing over it a time or two. Once anchored up all you will read is the depth and see a cionstant bottom and or/any structure youre sitting on top of. When there's structure it will stay constant on the screen creating a hugh "block" (usually solid unless it's just a limb coming off the bottom). If a fish swims underneath the sonar, as long as it stays in the "zone" of the sonar your unit will draw a constant line across the screen, but again, where the image first starts on the unit is "realtime". You may watch the line (fish) move up or down of suddenly end on the graph as the fish moves shallower or deeper/swims out of the sonar.

I'm definitely no expert when it comes to sonar so someone else will probably chime in and straighten out any false statements, but that's how I interpret what I see on my unit. I had the privledge of seeing a unit which supports maps and now I'm in the market for a new depth finder. I thought sonar was the cream of the crop when I bought my first unit about 3 years ago but now I've found out after seeing this other unit that I've just scratched the surface buying the bare minimum when it comes to depthfinders.:o Good luck with your graph. Spend time on the nwater playing with all the setting and learn all you can. After awhile you'll build alot of confidence in what youre seeing and actually start believing in it. Even with the units I have, I wouldnt go fishing if I didnt have mine onboard.;) Hope this helps!:)

Rule of thumb for a 20 degree cone is u see 3 feet of bottom for every 10 foot of depth.In other words your cone has formed a 36 in dia pie shape below boat. On some models if you turn off the auto setting & run gain all way up you may pick up a little bigger area & instead of a cone signal shape it will be like a school bell shape but u will also get alot of trash in pict.

Yup, whatever your depth, just divide by 3 and you will be close to your coverage.

Have you tried to find info on the internet (besides here)? I got some good info on youtube.

aj

When what ever you are looking at appears on the right hand part of the screen, your transducer is over it. So another words if your transducer is on the stern, when you see a drop off, it is under the boat. Naturally the faster you are moving, the faster you will pass it.