Free · no account needed

Know your boat is holding.

A precise anchor watch that sounds the alarm the moment you start to drag — and lets a second phone or a laptop ashore watch the boat with you. Works with the GPS you already have.

Free to use. No login — just share a code.

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Live anchor circle, drift distance & bearing, track history.

The anchor watch without the hassle

Most anchor apps make you create an account, and to watch from a second phone every device has to log into the same account. We threw all that out.

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No login, no registration

Open it and you're watching. No email, no password, no sign-up — and no personal data collected.

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No shared account to set up

Forget juggling the same login across phones. Share a 6-character code and any device can join the same watch.

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Mix any devices

An iPhone on the boat, an Android or a laptop ashore — they all follow the same anchor watch, live.

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Works with almost any GPS

Phone GPS, a Bluetooth receiver, or your chartplotter / NMEA / Signal K network. Use whatever you've got.

Use the GPS you already have

From the phone in your pocket to the chartplotter at the helm — Anchor Alarm Pro reads them all and automatically picks the most accurate fix it can see.

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Phone & tablet GPS

Built-in location on iPhone, iPad and Android. Nothing extra to buy.

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Bluetooth GPS

Pair an external BLE receiver (e.g. Garmin GLO, Bad Elf) that streams NMEA — better accuracy below deck.

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NMEA 0183

Read your boat's own GPS over the network — NMEA sentences via TCP or UDP from a multiplexer.

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Chartplotters

Garmin, B&G, Raymarine and other plotters that broadcast position on the boat's Wi-Fi network.

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Signal K

Connect to a Signal K server (e.g. Victron Cerbo GX) over WebSocket for a live position feed.

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Auto-select best

Leave it on Auto and it always uses the most accurate connected source — or pin one yourself.

Built for real anchorages

💸 Free to use

Open it and go — no account to create and no personal data collected. Set an anchor watch in seconds.

📡 Watch from anywhere

Leave one device on the boat and monitor from a second phone or a computer ashore. Share a 6-character code — that's the whole setup. Add as many devices as you like.

🔔 Alarms that reach you

Loud on-board alarm, plus push notifications to remote devices the instant the boat drags outside the safe zone.

🧭 Track & replay

See the boat's swing and track over the last 24 hours on the chart, so you can tell holding from dragging at a glance.

🔋 Light on data

Position updates are throttled and history is capped to 24 hours, so it sips battery and data.

💻 Works in the browser

A full anchor watch runs right in your browser — no install needed, and fully compatible with the iOS app over the same secure database.

How it works

  1. 1 On the boat, set the device to Vessel and drop the anchor at your position.
  2. 2 It publishes the boat's live position under a short share code.
  3. 3 On another phone or laptop, choose Monitor and enter that code.
  4. 4 If the boat leaves the safe circle, every device alarms.
Try the web app now