So I got out on the water today, and was pumped to use my depth finder finally.  Turned it on, and realized I have no clue what I'm really looking at.  I tried searching for a how-to, but came up empty.  Anyone know of a good place that would give someone a good idea of what they're looking at? 

Thanks!!

Did you get an owners manual and your not understanding that or are you talking about the depth finder?

There's a great sonar tutorial at:

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

"Depth finders" do more than tell you depth, but like any other electronic gizmo there is a learning process.

The bottom echo will change with changes in the composition of the bottom.

A smooth thin line indicates a fairly flat bottom.  As the line gets thicker, it can indicate a number of things including a rocky bottom.

Here's why.  The bottom line is created by the echo of the trandsducer beam from the bottom.

It transmits in an upside down cone shape.  So, depending on depth, it is sending radio waves not to one small point, but one area.

The deeper the water, the larger the area.

A smooth bottom will reflect the signal away from the transducer.  Only those directly beneath the unit will "return" to the transducer.

Those outside of the center of the transmission will bounce off the bottom away from the transducer.  Kind of like a billiard ball bounces off the cushions.  So, on a smooth bottom you get a narrow bottom echo on your display.

There is an exception, and that is a soft bottom where the signal penetrates a bit until it is reflected back.  The line on your display will be broader, but also not as dark on a monochrome.  On a color machine a soft bottom can be seen in blues and greens.  On a monochrome with shades of grays, it will not be as dark as a hard bottom.

A rocky bottom will produce a wider (from top to bottom) image of the bottom.  That is because rocks on the outer parts of the circle that receives transmission bounce the signal in many different directions, some of which return to the transducer.

Because the signal travels further to the perimeter of its circle, they also travel further back.  Though it may only be inches, and sometimes feet, the sounder shows them on the display, and a line that once was an eighth of and inch wide is now a quarter inch or more.

Once you learn how to "read" it, you will be able to identify vegetation, rocky, muddy, sandy bottoms, etc.

But for now.  Keep it simple.

If you have favorite places where you are fishing, study the bottom echo at those places on the display carefully.  Find more bottom like that, and fish it.

My problem is I'm turning the sonar on, and I look at the display, and I'm not really sure what I'm looking at. 

Thanks for the help!  I'm checking out the link now, and I'll be reading the tips about 20 times.   

This page has one of the best sonar tutorials I've seen online.  Really good info.

http://fishinweb.com/messages/messages/13028/13028.html?1258393767

There is a significant omission from that tutorial.

It is reading the bottom echo.  Mid water column echoes can be misleading.  I've found fish when nothing but the bottom shows on the sounder.

Granted, in most cases it is rocky bottom where fish can hold in pockets and therefore do not show up on the display.

As I have posted before, I was a commercial lobsterman for over 25 years, and knowing how to read bottom echoes is absolutely crucial to finding lobsters.

So, my focus was always on the bottom echo, and I learned to detect subtle changes many might ignore.

When I went to a Furuno color sounder from a paper recorder, those differences which were barely discernible on the paper machine stood out clearly on the color sounder.

Find a particular type(s) of bottom, and you'd find lobsters.

Fish move around, but the types of bottom that fish like to inhabit don't.  One day the image may contain a screen full of arches.  An hour or a day later, the same spot may show nothing.

Fish relate to structure, cover, food supply, and spawning areas.

In my opinion, it is of the utmost importance to be able to distinguish bottom types.  You will then be able to identify areas capable of holding fish.  You don't even have to understand what the bottom composition is.

When you see a particular echo(s) on the screen, you'll know that bottom can hold fish.  You'll also avoid those areas that are very rarely, if ever, productive.

That's not to say you should ignore images in the water column.  Those will vary.  Save for the appearance and disappearance of vegetation, bottom images will remain constant.

I took the boat to areas that I knew the bottom content.

   Like the boat ramp, its solid concrete, sandy swim beach, the dam and big rocks, passing over a tree, soft mudd, submerged vegitation, known xmas trees or brush.

    Once you have seen how these things appear, you will start to learn what are hard bottoms, soft bottoms and so on.

   Once you have seen what these appear like, then you can adjust intensity up and down to see what that does to your picture.

    I like to go to bridges, going slowly parallel to the bridge pilings, how many feet past the column does it take to show up on the screen?  are you ten feet past the piling when it shows up on the screen, note your boat speed.

    Easiest way to learn your graph is to use it in areas that you know what is down there, that takes guess work out of what you are reading.

 

I'm telling you Rhino, I really need to get out on the boat one day with you.  I could probably learn a ton on using a sounder.  Every thread that comes up on the subject you have some extremely useful information to share.