Boat Knot Meter: Anchor Watch
Marine GPS speed, drift alarm
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
Boat knot meter with anchor watch and no-wake alarm. SOG, COG, drift alarm, GPX export. 0.1-knot precision. Zero ads. Zero accounts. Works offline once GPS locks.
The boat knot meter app that doesn't lie. Real GPS speed in knots, with anchor watch and no-wake alarm built in. Zero ads. Zero accounts. Zero tracking. Works offline once you have GPS lock — no cell signal needed in open water.
Boat speedometer for sailors, fishers and small-craft owners. Whether you sail a dinghy or sailboat, troll for fish, ride a jet ski or motoryacht, paddle a kayak or stand-up paddleboard (SUP), TrueFix Marine shows your true speed over ground (SOG) in knots, with 0.1-knot precision when you need it.
Marine GPS, built for the boat that doesn't have one.
- Speed Over Ground (SOG) in knots, km/h, mph or m/s
- Course Over Ground (COG) — compass + degrees
- Captain Mode — giant digits readable from the helm 2 m away
- Marine theme — high-contrast deep navy, full-sun friendly
Anchor Watch (drift alarm)
Drop anchor, set the safety radius (10, 25, 50 or 100 m), and sleep easy. The app sounds an audio + vibration drift alarm if your boat drifts beyond the radius. Background monitoring continues with the screen off when you grant Always Location.
No-Wake Alarm
Country presets — US 5 mph, UK 6 kn, IT 3 kn, FR 5 kn, ES 3 kn, DE / NL 6 km/h, AU 4 kn — auto-detected on first run and editable per harbour or marina. A red banner plus haptic alert fires the moment you exceed the no-wake limit.
Honest GPS quality
TrueFix shows fix accuracy at all times: Waiting, OK, Weak, Lost. A glitch guard suppresses GPS spikes near cliffs, bridges and high-rise marinas, so MAX speed never lies. When the signal degrades, the speed digits dim — instead of pretending everything is fine.
Trip Log + GPX export
Distance in nautical miles, max and average knots, time-at-speed buckets (Idle / Sail-troll / Planing / Fast). Export your day as GPX 1.1 for OpenCPN, or as CSV for spreadsheets and trip logs.
Privacy by design
Zero data leaves your phone. No analytics, no crash reporting, no cloud, no third-party tracker. There are no accounts because we don't have a server. The only network call the app makes is the optional Send Feedback form in Settings — explicitly user-initiated.
Out of scope by design
TrueFix Marine is a boat speedometer and anchor watch app, not a chartplotter. No AIS, no electronic charts, no autopilot — focused and reliable. Use it alongside your chartplotter, not instead of one.
Drive Mode also available
For road use, switch in Settings → Advanced → Modes. The app also works as a GPS speedometer for car, motorcycle or bicycle, with a HUD windshield reflection mode and lock UI to prevent accidental touches while driving.
Not a substitute for certified marine instruments. Not for navigation, collision avoidance, or open-ocean passage. Always carry certified backup equipment (compass, chart, VHF radio, life jackets).
Ratings & Reviews
- This app hasn’t received enough ratings or reviews to display an overview.
The developer, lapnito.cz s.r.o., indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- lapnito.cz s.r.o.
- Size
- 24.6 MB
- Category
- Navigation
- Compatibility
Requires iOS 13.0 or later.
- iPhone
Requires iOS 13.0 or later. - iPod touch
Requires iOS 13.0 or later. - Mac
Requires macOS 11.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Location
- This app may use your location even when it isn’t open, which can decrease device battery life.
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- Copyright © 2026 lapnito.cz s.r.o.