38 GPSMAP 4000 Series Owner’s ManualconfIGurInG the unItconfIGurInGthe unItSetting Navigation AlarmsTo set a navigation alarm, from the Home screen, select Configure > Alarms > Navigation.Anchor Drag—set an alarm to sound when you exceed a specified drift distance.Arrival—set an alarm to sound when you are within a specified distance or time from a destinationwaypoint.Off Course—set an alarm to sound when you are off course by a specified distance.Setting System AlarmsTo set a system alarm, from the Home screen, select Configure > Alarms > System.Clock—set an alarm using the system (GPS) clock. The unit must be on for the clock alarm to work.battery—set an alarm to sound when the battery reaches a user-determined low voltage.GPS Accuracy—set an alarm to sound when the GPS location accuracy falls outside the user-determined value.Setting Sonar AlarmsTo set a sonar alarm, from the Home screen, select Configure > Alarms > Sonar.NOTE: You must have an optional sonar module (and a transducer connected to the soundermodule) wired via NMEA 0183 or connected to the Garmin Marine Network to receive sonarinformation.Shallow Water/Deep Water—set an alarm to sound when the depth is less than or greater than thespecified value.Water Temp—set an alarm to sound when the transducer reports a temperature that is 2° F (1.1° C)above or below the specified temperature.Fish—set an alarm to sound when the unit detects a suspended target of the specified symbols.Setting Weather AlarmsTo set a weather alarm from the Home screen, select Configure > Alarms > Weather.NOTE: You must have a subscription to XM WX Weather and the optional GDL 30/30A moduleconnected to the Garmin Marine Network to view weather information. Refer to page 53 for moreinformation.Configuring My BoatTo configure settings for your boat - from the Home screen, select Configure > My boat.Auto Guidance—set the Auto Guidance parameters for your boat:Safe Depth—set the minimum depth (refers to the chart depth datum) to allow whencalculating an auto guidance path.Safe Height—set the minimum height (refers to the chart height datum) of a bridge that yourboat can safely travel under.••