Garmin GPSMAP 721 Owner's Manual - Page 19

Viewing Tide Station, Current Station, or Celestial Information for a Different Date 1 Select Nav Info > Tides & Currents. 2 Select Tides, Currents, or Celestial. 3 Select an option. • To view information for a different date, select Change Date > Manual, and enter a date. • To view information for today, select Change Date > Current. • If available, to view information for the day after the date shown, select Next Day. • If available, to view information for the day before the date shown, select Previous Day. Viewing Information for a Different Tide or Current Station 1 Select Nav Info > Tides & Currents. 2 Select Tides or Currents. 3 Select Nearby Stations. 4 Select a station. Viewing Almanac Information from the Navigation Chart 1 Select Charts > Navigation Chart. 2 Select an area on the map. 3 Select Information. 4 Select Tides, Currents, or Celestial. Split-Frequency Sonar View In the split-frequency sonar view, one side of the screen shows a full-view graph of high frequency sonar data, and the other side of the screen shows a full-view graph of lower frequency sonar data. NOTE: The split-frequency sonar view requires the use of a dual-frequency transducer. Select Sonar > Split Frequency. Pausing the Sonar Display From a Sonar view, select Menu > Pause Sonar. Creating a Waypoint on the Sonar Screen 1 From a Sonar view, select Menu > Pause Sonar. 2 Select the location of the waypoint. 3 Select Mark or New Waypoint. Adjusting the Gain on the Sonar Screen You can control the sensitivity of the sonar receiver. To see more detail, increase the gain. If the screen is cluttered, decrease the gain. 1 From a Sonar view, select Menu > Gain. 2 Select an option: • To increase or decrease the gain manually, select Up or Down. • To allow the chartplotter to adjust the gain automatically, select an automatic option. Sonar When properly connected to an optional Garmin sounder module and a transducer, your compatible chartplotter can be used as a fishfinder. There are three different sonar views to help you view the fish in the area: a full-screen view, a splitzoom view, and a split frequency view. Full-Screen Sonar View The full-screen sonar view shows a large image of the sonar readings from a transducer. The range scale along the right side of the screen shows the depth of detected objects as the screen scrolls from the right to the left. Select Sonar > Full Screen. Range adjustment controls À Position information Á Suspended targets or fish  Bottom of the body of water à Range or depth of the water Ä Transducer frequency Å Split-Zoom Sonar View The split-zoom sonar view shows a full-view graph of sonar readings, and a magnified portion of that graph, on the same screen. Select Sonar > Split Zoom. Adjusting the Range of the Depth Scale You can adjust the range of the depth scale that appears on the right side of the screen. 1 From a Sonar view, select Menu > Range. 2 Select an option: • To allow the chartplotter to adjust the depth scale automatically, select Auto. • To increase or decrease the range of the depth scale manually, select Up or Down. TIP: From the sonar screen, you can select or to manually adjust the range of the depth scale. Setting the Zoom Level on the Sonar Screen 1 From a Sonar view, select Menu > Zoom. 2 Select an option: • To zoom in on the sonar data from the bottom depth, select Bottom Lock. • To set the depth range of the magnified area manually, select Set Zoom, select View Up or View Down to set the depth range of the magnified area, and select Zoom In or Zoom Out to increase or decrease the magnification of the magnified area. • To set the depth and zoom automatically, select Set Zoom > Auto. Selecting Frequencies You can indicate which frequencies appear on the sonar screen when using a dual frequency transducer. 1 From a Sonar view, select Menu > Frequency. 2 Select an option: • To sweep each pulse through a range of frequencies to deliver shallow-water-like target separation at extremely deep depths and at low frequencies, select Chirp. This is useful mainly for very deep, offshore waters and when targeting some species of fish. Sonar 13