Stop worrying every time you drop anchor.
Anchor Alarm turns your iPhone into a professional boat anchor sentinel that never sleeps. When the wind picks up at 3 AM and your boat starts dragging, you get a critical alarm, even if your phone is silent, even if the app is closed. Real-time GPS marine watch monitoring for your vessel. Your boat. Your peace of mind.
WHY BOATERS CHOOSE THIS FREE ANCHOR ALARM:
► NEVER MISS A DRIFT
Real-time GPS monitoring with advanced Kalman filtering delivers meter-accurate position tracking for boat anchoring. The app continuously calculates your distance from the anchor and triggers an escalating alarm the moment you drift outside the safety zone. Visual warning. Audio siren. Vibration. Flash. We don't let you sleep through it.
► WORKS IN BACKGROUND, AND OFFLINE
Grant "Always" location access and this anchor watch keeps monitoring while your screen is off, while you're using other apps, or when your boat has zero internet connectivity. The alarm sounds regardless. That's the whole point of a reliable marine safety app.
► FOUR ANCHOR ZONE TYPES
• Circle: classic radius-based monitoring for any anchorage
• Sector: wind-based swing monitoring for exposed bays
• Polygon: custom shapes for irregular, rocky anchorages
• Ellipse: tidal swing monitoring for areas with strong currents
Pick the zone that matches your conditions. Auto-calibration adjusts the zone based on your initial swing pattern, giving you a smarter anchor watch experience.
► COMPLETE NAUTICAL CHART PLOTTER
Built-in OpenSeaMap charts with seamark overlays for marine navigation. Explore harbors, marinas, lighthouses, buoys, and nautical POIs, all from live OpenStreetMap data. Toggle between anchor monitoring mode and free chart exploration. Plan your route. Scout your next anchorage. All in one app.
► SMART DRIFT PREDICTION
Anchor Alarm doesn't just react, it warns you before the drift happens. Predictive algorithms combine real-time GPS data with weather conditions (wind speed, direction, barometric pressure) to estimate where your boat will drift next. Get ahead of the problem before it wakes you up.
► WEATHER AT A GLANCE
Real-time weather from OpenMeteo integrated directly in your GPS anchor monitoring screen. Wind speed and direction, atmospheric pressure, and severe weather alerts, all at a glance. Essential for any sailor.
► POWER MANAGEMENT THAT MAKES SENSE
Four power profiles to match your situation:
• Maximum Precision: continuous GPS, highest accuracy
• Balanced: adaptive sampling for overnight anchor monitoring
• Battery Saver: reduced frequency for long passages
• Critical Mode: minimal monitoring when battery is low
Estimated runtime display so you know exactly how long you can monitor.
► APPLE WATCH COMPANION
Anchor Alarm on your wrist. Real-time sync with your iPhone. Glanceable complications. Critical alerts even when your phone is in the cabin. Remote arm/disarm. Standalone emergency mode for when you're away from the helm.
► YOUR DATA, YOUR DEVICE
All anchor session data stays on your iPhone. No cloud upload, no account required. Export your sessions as CSV, GPX, or JSON for logbook keeping. Full privacy. No marine data leaves your device.
► SUBSCRIPTION DETAILS
Anchor Alarm is free to download and use with basic features. Premium unlocks unlimited anchors, advanced nautical charts, custom alarms, advanced marine analytics, and removes ads.
Three options: annual, with a 7-day free trial, monthly, or a one-time Lifetime purchase that unlocks Premium forever. The price for your country is shown in the app before you buy.
Payment charged to your Apple ID account. Subscription auto-renews unless canceled at least 24 hours before the current period ends. Manage and cancel anytime in your Apple ID settings.
Privacy policy: https://privacypolicyhub.vercel.app/ancorasicura/en
Terms of use: https://privacypolicyhub.vercel.app/ancorasicura/en
Built for the sailing community, by sailors.
