Garmin GPSMAP 3205 Owner's Manual

Also see for GPSMAP 3205 - Marine GPS Receiver: Installation instructions Installation instructions Quick reference guide Owner's manual Template manual

Contents

Garmin GPSMAP 3205 Owner's Manual Manual pdf 82 page image

74 GPSMAP 3205 Owner’s ManualU SING SONAR > U NDERSTANDING SONARThe wide beam is more helpful in shallow water, because it gives you a muchwider view of objects in the water, including areas beyond the sides of your boat.At a 30-foot depth, the wide beam covers the area of approximately a 20-footcircle.Understanding the Sonar DisplayOne of the first things to understand about sonar is that the transducer sends abeam down to the bottom of the water, much like the beam of a flashlight. Thebeam starts small near your vessel and expands as it gets to the bottom.The Sonar Page does not show a three-dimensional representation of theunderwater environment. Instead, the display is in two dimensions, much likeif you took a picture of an aquarium. Only the depth of the item in the wateris shown. The Sonar display does not show you where an item is locatedhorizontally in the water, as shown in the following illustrations. The fish is notdirectly above the tree in reality, but it can look like it is on the Sonar Page.The strongest sonar returns appear on your screen as the most intense solidcolor (depending on your selected color scheme; red is the default). The weakestreturns appear as the less intense, less solid colors (blue is the default).The bottom of the water is always going to be the strongest signal, and thereforethe most intense color. The bottom is the continuous, intensely-colored linerunning across the bottom of the screen. The GPSMAP 3205 includes the latesttechnology in interpreting bottom signals; it can see through fish, structures,and thermoclines (shown in the weakest colors). Large schools of fish or densestructures close to the bottom can affect water depth return readings.NOTE: If the GPSMAP 3205 is unable to track the bottom for any reason, thedigits in the depth window flashes on and off to alert you that the unit is nottracking the bottom.At the top of the screen, you might see a grouping of intense colors. This area issurface clutter, which can be caused by waves or any other sonar interference atthe surface of the water. Too much surface clutter can obscure your view of fish.You can turn down the Gain setting to reduce this surface clutter.Between the bottom and the surface clutter, you see fish in the previousillustration. Here, the fish appear as arches. Actual fish returns might not alwaysappear as perfect arches, due to the speed, fish orientation, or other conditions.You can turn on the Fish Symbols setting if you want to see on-screen fish in afish shape.The strength of the sonar return can also help you interpret the hardness of thebottom of the water. The thicker the bottom line, the harder the bottom.Hard Structure Soft Structure