GPSMAP 3005C Owner’s ManualusIng sonAr > sonAr tAbMarking an Underwater WaypointYou can mark waypoints that are under the surface of the water.To mark an underwater waypoint:1. On the Sonar Page, use the ROCKER to move the pointer to the locationyou want.2. Press and release ENTER/MARK. The Review Waypoint Page appearswith the waypoint’s coordinates, default name, and pointer depthautomatically filled in.3. To change the name, symbol, or depth, highlight the appropriate field, andpress ENTER. Make any changes, and press ENTER when finished.4. Highlight OK, and press ENTER to return to the Sonar Page.5. Press QUIT to resume scrolling.Sonar TabWhen a GSD 20, GSD 21, or GSD 22 is connected to the GPSMAP 3005C, andeither the Auto-Detect Services or Sonar check box is selected on the Systemtab, the Sonar tab appears on the Main Menu.Use the Sonar tab to set up the Sonar Page. The Sonar tab has three sub tabs:General, Graph, and Water Temp.To access and change a setting on the Sonar tab:1. Press the Sonar Setup soft key to open the Main Menu. The Sonar tab isautomatically selected.2. Highlight the setting you want to change, and press ENTER.3. Press QUIT to return to the Sonar Page.General Sub TabUse the General sub tab to select the water type, depth number, automatic scrollspeed limit, scale, keel offset, and transducer type. The available General sub taboptions are as follows:• Auto Gain—controls the aggressiveness of the Auto Gain when the Gainoption is set to Auto. The higher the setting, the greater the number oftargets appear on the screen. The lower the setting, the less clutter on thescreen. The settings are low, Medium (default), and high.• Auto Color Gain—controls what colors are applied to the objects on thescreen when the Color Gain option is set to Auto. Color DCG™ is basedon depth and makes it easier to spot subtle changes in bottom conditionsor fish sizes. DynaColor™ (default) represents the latest in sonar datapresentation and is recommended for all applications. The presentation isbased on bottom strength. It makes the bottom and the fish easier to see andrequires fewer adjustments.sonar