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Anchor Alarm for AndroidThe boat should swing.The anchor shouldn’t.

Set a point. Give your boat room to swing. Atlas watches the GPS track for a confirmed boundary breach, sustained outward movement or lost GPS.

Explore alarm setupSee how it works

Active monitoring works offline in the Android app. The browser offers a setup preview.

Illustration of a boat swinging around a fixed anchor point, with its curved GPS track inside the alarm boundary.NPLAN VIEW · ILLUSTRATIONALARM BOUNDARYANCHOR POINTRoom to swing
Illustration · a normal swing inside the set radius. This is not a live position or a navigation chart.

01 / How the anchor alarm works

Three tracks. Three different stories.

Movement alone doesn’t tell you whether the anchor is holding.

A swing

A change of wind can move the boat around the anchor point. Leave room for that movement when you set the radius.

An outward trend

Atlas looks for sustained movement away from the set point near the boundary. A confirmed radius breach can also trigger an alarm. Neither reading proves what the anchor is doing on the seabed.

A GPS jump

A single erratic fix is not treated as proof of dragging. Poor accuracy and loss of usable GPS are watched separately.

Before starting, choose Notice or Alarm for each event in settings. Radius breach, outward movement and GPS loss default to Alarm; weak GPS and bearing veer default to Notice. Bearing veer is watched in Manual and 2-step modes.

02 / Set the watch

Start with where the anchor is.

Your phone knows where the phone is. The setup chooses the point the boat will be watched around.

  1. Simple

    Use once the boat is settled. Centre the circle on an averaged GPS position of the phone aboard, rather than the anchor on the seabed. Set the radius to allow for the boat’s movement around that point.

  2. Manual

    Estimate the anchor position using boat length, rode out and a locked bearing. Review the suggested radius before starting.

  3. 2-step

    Record when the anchor touches bottom, then reverse and pay out rode while keeping the setup open. Once snubbed, start the watch; the circle stays at the recorded drop point.

The radius is your alarm boundary, not a verdict on safe anchoring. Allow for your boat, rode and GPS accuracy, and check the available room against the chart and what you see on deck.

Before you leave the screen.

Check location access, notifications and battery settings. Review the alarm radius and event settings. Keep the phone aboard and powered; Android battery restrictions can interrupt the watch.

An aid to the watch.

GPS tracks cannot confirm the anchor’s grip on the seabed. Keep a proper watch and assess the conditions on deck. Active monitoring is supported in the Android app; iOS and a sleeping browser are not supported alarm platforms.