Lately i've been really concentrating on being more precise reading a fish finder .. I've always been extremely good at estimating .. But with a fish finder , I'm not sure what i'm estimating distance wise .. Is there some sort of formula i could use on estimating exactly where them fish are ? Ex... Let's say my transducer is mounted in the back of my boat , I have a hummingbird with a 5" screen , There's 1 fish on my screen and it happens to be on the rightside of the screen , Therefor the fish is almost off my screen , Is there a way to guesstimate how far that fish is behind my boat ? And how far to the left or right of my boat's position could it be ? Thanks for your time !

 

 

If the fish is almost off the screen on the RIGHT side, it is within the cone angle of the transducer and is under the boat's transom and is just appearing on the display.

There is no formula to account for the variable speed of the boat and variable screen scroll speed in relation to a displayed object. You would have to measure a run for distance with a constant boat speed with a set screen scroll speed to get any figure to work with.

There is no way with 2D sonar to know which side of the boat the fish may be. If you get a quad transducer, you can get that information.

You  may want to get a friend throw a spinner bait out of the back of the boat and see if you can see it on the depth finder. Start out yo-yoing below the transducer and see how it show up on the screen. This would give you a ideal of what you are seeing on the screen.  I have a different brand of depth finder and to see more detail, I have turned off the fish ID. I know from experience with the depth finder and a underwater camera, the auto fish ID will show a big fish for 3 small fish grouped together.  I prefer to see the fish arches.

I have turned off the fish ID. I know from experience with the depth finder and a underwater camera, the auto fish ID will show a big fish for 3 small fish grouped together. I prefer to see the fish arches.

That alone is one of the best things to do.

Like Wayne said, if it is on the right side of the screen it just showed up somewhere in the cone angle.  Don't use the machine to find fish.  Use it to find fish holding structure.

Do a google search for Lowrance sonar tutorial it is a good read and explains alot about how these things work.

Good Luck,

TomD

http://www.lowrance.com/Support/Tips-and-Tutorials/Sonar-Tutorial/

http://www.lei-extras.com/tips/sonartut/fisharches.asp

First thing I do is turn off that stupid fish ID function. Just worthless and you never know if it's a fish or a small log, turtle, etc. floating between the bottom and the surface.

The only time I ever use my sonar to find fish is in deeper water then and only then its used to lock on or pin a fish so i can watch my lure go down to it but other than that I use my sonar primarily (99%) to locate structure and I also use it for water depth in stained waters.

The reply that rattleheadbaits sent to you would be the best thing to try but make sure you read your owners manual you may have to make a lot of changes to it too be able to see it even then it may not be able to see it.