Anchor Drag Alarm
Drops your anchor position from the device GPS and watches your drift. If the boat moves outside the radius you set, a visual and audible alarm fires. Keep the screen on and device charged while in use.
Important: Your device volume must be turned on (not muted) for the anchor drag alarm to sound. Keep the ringer/volume up while anchored.
Screen must stay on & unlocked: monitoring, GPS updates, and the alarm only run while this page is open and in the foreground. The wake lock keeps the screen awake, but if you manually lock the screen or switch apps, the alarm will be silenced. For true locked-screen / background monitoring (even while the phone sleeps), a native iOS/Android build is required — the web version cannot run while the screen is locked.
GPS position
37.23748, -121.82779
±1916647 m accuracy
Distance from anchor
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Anchor Watch is a situational aid, not a substitute for a dedicated anchor alarm or watchkeeping. GPS accuracy and battery life vary by device.