How Does A Fish Finder Work?

[BasskingKeith]

Yeah, the title says it all. But let me be clear, since there's quite a few different finders out there. I'd like to know how the newest ones work, the ones you see on Bassmasters and TV shows. The thing is, how do you correlate what you see on the graph to the position of the boat? Is what you see directly under you, in front of you, behind,etc. how far away? I don't have a boat, but I always wanted to know.

[Fishing Rhino]

What you see is and was directly under the boat, unless you use the display in the circular, flasher mode.   As the image scrolls across the display everything but the latest vertical line of pixels is a recorded history of the bottom you passed over.  To be more precise it shows what was under the transducer.

 

To keep it simple.  As soon as you see a bottom feature that interests you, throw a marker buoy over the side.  That marker buoy will not land on that piece of bottom.  Depending on boat speed it will be beyond that patch of bottom you saw.  So, when you drop the buoy, make a 180 degree turn.  As you pass the marker buoy, you should see that patch of bottom appear on the display.  Drop another buoy when you see it.  That patch of bottom will be between the two buoys.

 

If your unit has a mapping feature, you may be able to "mark" that spot.  It will work the same way as the marker buoys.  I like to use marker buoys because they provide clearly  visible points of reference.  I use them to mark contour lines, and edges of vegetation.  While it's possible to do it with some electronics, I prefer the buoys in most situations.

[Wayne P.]

http://support.lowrance.com/system/selfservice.controller?CONFIGURATION=1001&PARTITION_ID=1&secureFlag=false&TIMEZONE_OFFSET=&CMD=VIEW_ARTICLE&ARTICLE_ID=2967

[Sam]

Actually, what you see is to your rear on the right hand side of the boat where the transducer is mounted or on the trolling motor.

 

So when you see items on your screen only the far right 1/4 inch is what is actually under the rear right of the boat.

 

This is why you throw out two buoy markers when you want to fix on a spot so you can line them up in the water and track back to the excact location you want to fish with the understanding that the structure and fish you see are actually behind you.

 

Thanks to the Sonar Professor for teaching me this and a lot of other stuff, too.

 

http://www.sonargpsuniversity.com/

 

You can meet him at the Richmond Fishing Expo next weekend.

[BasskingKeith]

Sweet, that sounds awesome and fun finding things with that sonar. More simple than I previously thought, too.

[Fishing Rhino]

The more you do it, the simpler it becomes.  Now, here's another tidbit for you to digest.

 

You've marked your spot/area, and you find it holds fish.  Pay attention to the bottom echo.  If it's a monochrome unit, the darker the line, the harder the  bottom.  So, that productive patch of bottom shows you a broad or narrow echo.  It may show you vegetation growing up from the bottom.  It may show as an irregular, jagged line.  Whatever it shows, fix that image in your mind.  Then cruise around looking for another patch of bottom that produces the same image, and close to the same depth.  Chances are good that it will also hold fish.

 

Sometimes these will be fairly small.  Other times they may cover a large area.  You are prospecting.  The sonar/fishfinder/sounder is an invaluable tool.  The more you use it, the more proficient you will become with it.

 

It is awesome, and it is fun. 

[Sam]

Bank, the units work on sonar.

 

The transducers send out the sonar waves and the waves bounce off what they hit back to the transducer which transmits them to your unit's screen.

 

Bass and other fish look like boomarangs.

 

The sidescan, downscan and Hummingbird's 360 Imaging works the same way.

 

I am sorry to say that I do not know the principals of the these newer units but if you contact The Professor he can let you know how they work and on what prinicpal.

 

If I remember I will ask him this Friday at the Richmond Fishing Expo or get off my lazy behind and slip in one of his DVDs which explain how the older units work.