Anchor Alarm

A GPS anchor watch for iOS and Android. Sleep knowing your phone is watching the anchor.

App store listings for iOS and Android will be linked here at launch.

How it works

1. Drop the anchor

Anchor your boat, then mark the spot with your phone’s GPS or enter coordinates by hand.

2. Set a radius

Choose how far the boat may swing. The zone is shown on the dashboard and on the map.

3. Start monitoring

The app keeps watching in the background and sounds an alarm if the boat drifts outside the zone.

Screenshots

Anchor Alarm dashboard showing 24 m drift to the anchor against a 50 m limit, GPS accuracy, position age and battery, with status OK — Dashboard while monitoring

Map showing the anchor and a keyhole-shaped alarm zone with the boat’s track inside it — Alarm zone and track on the map

Alarm screen reading Outside monitored area, 40 m, 15 m beyond the limit, with Silence 5 min and Stop Alert buttons — Alarm when the boat leaves the zone

Remote watch screen with a QR code and check phrase, showing one phone following — Share the watch with a second phone

The following phone showing the boat’s drift of 30 m with the status Following the boat phone — Follow the boat from ashore

History screen listing two past anchoring sessions, one with an alarm — Past anchoring sessions

Demo video

A two-minute walkthrough on a real Android phone: start monitoring, lock the screen, hear the alert, share the watch with a second phone and stop monitoring.

Features

Drift alarm with an adjustable radius, plus warnings for weak GPS and low battery.
Background monitoring that keeps running with the screen locked.
Audible alerts you can silence for five minutes or stop once you have dealt with them.
Maps with the anchor, alarm zone and your track, plus optional seamark overlay and offline map downloads.
History of your anchoring sessions, stored on your phone.
Remote watch (optional): follow the boat phone’s anchor watch from a second phone ashore, with an alarm there too.
Block Internet switch for completely offline use.
No account, no subscription, no ads.

Your data stays on your phone

Your position and anchoring history are stored only on your device.
Arxiflex does not collect, receive or store any of it. There are no accounts, analytics, ads or trackers.
The only network traffic is map tiles and, if you choose to use it, Remote watch between your own phones.

Read the full privacy policy

Important

Anchor Alarm is a supplementary aid and not a substitute for proper seamanship, an anchor watch or marine safety equipment. GPS accuracy and phone behaviour vary between devices and conditions, so always test the alarm before you rely on it.