Thread: New Boater

what lakes are you going to fish.start with drop offs, humps, creek channels I would start at 12 feet down to 20 . vary your depth on each rod till ya find them then set them all to that depth

You need to read this thread.http://www.crappie.com/gr8vb3/showth...91646#poststop

Getting The Most From Your Graph (Sonar, Sounder, Fishfinder Thangy, etc.)

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Questions on how to properly adjust graphs and decipher what they show on the screen have come up many times on this board. The following is what I have learned from using several different graphs over the years and may be something that could be made into an article for future reference. Please consider it a rough draft. I’m open to suggestions so if I’ve left anything out or not explained anything adequately please feel free to offer any suggestions that will make it more complete and concise. I’ll try to get some pictures to add in the near future. If it turns out to be helpful and worthwhile I’ll ask Ed to make it a permanent article. A lot of this is pretty basic, long and drawn out (boring) but I've tried to make it helpful for someone that has never used a graph before.

Fish Arches - What Am I Seeing?

In order to get a “fish arch” (like the manufactures lead us to believe we should be seeing on our graphs) a fish must pass completely through the “cone” or view of the transducer from one side to the other within a narrow speed range depending several variables without changing depth when either the boat passes over the fish or the fish swims under the boat.

Think of your graph screen as a composite picture of individual sonar returns. The transducer sends intermittent sound waves or “pings” down into the water and records how long it takes for each ping to return to the transducer as well as how loud that signal is when it bounces back up from the bottom or other object and returns to the transducer.

The returning sound waves are "painted" on the graph screen by filling in pixels with shades of gray or colors depending on whether you have a "Grayscale" or a color graph. The sound waves are broadcast into the water in a "cone" or circle that is narrow at the transducer and widens until it meets the bottom. Only objects that are in the cone or view can be detected by the graph.

Think of each horizontal pixel on your screen as one ping or one still photograph of what was in the view at that instant. As long as the object being painted on the screen stays in the view of the transducer the pings will continue to paint or fill in on the screen. Think of each vertical pixel as one volume setting. The louder the ping comes back the more vertical pixels it will paint and the darker or "louder" colors (on a color graph) it will paint them depicting higher volume. Higher volume means the sound wave bounced off a larger and/or denser object.

Also, note that the display on your screen is simply a short history of what your boat passed over or what passed under your boat. The most recent information comes into view on the right side of your screen and then moves across and off your screen to the left. Depending on your boat speed and scroll speed (speed at which information passes across your screen), what you're seeing on your graph isn’t necessarily under your boat and can actually be quite a ways behind you.

Arches are created because as a fish passes through the view or “cone” of the transducer it is farther from the transducer when it is at the edge of the cone and closer to the transducer when in the center of the cone. The width of the arch depends on several factors including, how fast the fish passes through the cone and also how fast your Scroll Speed is set.

The cone angle also affects fish arches because at a given speed (boat or fish) and scroll speed it takes longer for a fish to pass through a wide cone than a narrow cone at any given depth. Varying depths of fish also affects the arches because the cone gets wider as it gets deeper so the deeper a fish is the longer it takes it to pass through the cone and visa versa because of the difference in the distance across the cone at different depths.