# NaviLog: Sailing Logbook — Anchor alarm & GPS trip log

> Anchor alarm & GPS trip log (iPhone/iPad app by Felix Bartschi.)

- Source: https://appshunter.io/ios/app/navilog-sailing-logbook/id6790909811 (this page in markdown: same URL + `.md`)
- Developer: [Felix Bartschi](https://appshunter.io/developer/6790909813)
- Category: Navigation, Utilities
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 15.0 · 40 MB
- Languages: American English, German (Germany)
- Released: 2026-07-23
- Data updated: 2026-11-10

## What is NaviLog?

NaviLog — The Digital Logbook for Skippers

NaviLog turns your phone into a complete sailing logbook: automatic GPS track recording, a physics-based anchor alarm, one-tap man-overboard marking and a barograph with storm warning — all working offline and without an account. Your logbook belongs to you: it lives on your device, and goes to the cloud only if you switch on backup yourself.

AUTOMATIC GPS TRIP LOGGING
• Start a trip and NaviLog records your route in the background — even with the screen locked, no internet needed
• Distance in nautical miles or kilometers, duration, average and maximum speed
• Smart GPS filtering removes outliers for clean, accurate tracks
• Notes, weather and crew for every leg of your voyage
• Engine hours counter per trip and per yacht

BAROGRAPH & TRIP STATISTICS
• Every log entry saves the pressure from your phone's built-in barometer — measured on board, not taken from a forecast
• Barograph per trip: the pressure curve right below speed and temperature on one time axis, like a meteogram
• Lowest and highest pressure, biggest fall and rise — a fall of 3 hPa in 3 hours is marked as a gale sign
• The live barograph records during every trip and while the storm alarm is on, and keeps the last 7 days

ANCHOR ALARM (ANCHOR WATCH)
• Physics-based swing circle calculated from chain length, water depth, bow height and boat length — not just a plain radius
• Supports tide, mooring type and even a second anchor
• Pre-alarm, GPS-loss alarm and low-battery warning
• Adjust anchor position and chain length while the watch stays armed
• Wind and swing history recorded for every anchorage
• iPhone: the anchor alarm is reliable while NaviLog stays open (Apple limit)

MAN OVERBOARD (MOB)
• One tap marks the position instantly and guides you back with live bearing and distance
• Works with or without an active trip recording

WEATHER & STORM ALARM
• Marine weather and wind forecast for your current position (online)
• Pressure-drop storm warning from your phone's barometer — works completely offline, far from any coverage

SEA CHARTS & OFFLINE MAPS
• OpenSeaMap seamark overlay: buoys, lights, fairways on the map
• Download chart regions before you cast off and review your tracks offline (Pro)

FOR SKIPPER & CREW
• Crew, skipper and yacht profiles, official crew lists
• Checklists with templates (departure, safety briefing, engine check …)
• Sea-miles certificates for licence training and charter proof

EXPORT, BACKUP & SYNC (PRO)
• Complete logbook as PDF — now with a barograph page — and sea-miles certificate
• Tracks as GPX for OpenCPN, chart plotters and other apps
• CSV import/export of trips, crew, yachts and anchor history
• Optional cloud backup: your trips on phone and tablet, restored on a new device

MADE FOR NIGHT WATCHES
• Night-watch mode in red-on-black to protect your night vision
• Dark mode, fully localized in English and German

PRIVACY FIRST
• No account needed, no ads, no tracking of your behaviour
• Your logbook stays on your device unless you turn on cloud backup
• Optional online features (weather, place names, map tiles) contact their services only when you use them

WHO IS NAVILOG FOR?
Sailors, skippers, charter crews, motorboaters and liveaboards — for coastal cruising, blue-water passages, regattas, sailing school and logging licence miles. If you have ever looked for a free sailing logbook app with an anchor alarm and a barograph that work offline, this is it.

NaviLog is free as a full logbook with GPS tracking, anchor alarm, MOB and barograph. A single one-time purchase unlocks Pro (PDF/GPX/CSV export, cloud backup, crew lists, templates, offline chart download) — no subscription, ever.

Note: NaviLog is a logbook and an aid to good seamanship — it does not replace official navigation equipment, weather services or safe anchoring practice.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Pro Upgrade | $6.99 | one-time |


## Is NaviLog safe?

Not enough ratings yet to assess NaviLog.

## Is NaviLog legit?

NaviLog: Sailing Logbook has limited verification signals. The AppsHunter Legitimacy Score for NaviLog is 58 out of 100 points across 7 verification signals from App Store and developer data.


## Version history (last 5 releases)

### 2.7.2 — 2026-11-08

Minor improvements.

### 2.7.1 — 2026-11-02

Heel & sea state
- New: pitch (bow up/down) and pitching (amplitude and period) on the heel page. Heel is now the sideways tilt only — pitching used to be counted in and made the heel read high. Rolling and pitching are measured separately along the boat's axes.
- Heel card: its own waves icon instead of the sailboat (it read like a second status), a "Calibrate" button while upright is not yet known, pitching in the second line; now above the statistics so the floating buttons no longer cover it.
- Heel page: "Calibrate upright" right under the gauge instead of below the statistics.

Tracking
- The status row (propulsion/position) is tappable after Start: it says "tap to set" while nothing is set and opens the entry dialog with the likely switch preselected (sailing ↔ motor).
- The manual entry button is labelled ("Log entry") instead of a bare icon.

Barograph & hiking
- Height chart and the GPS height of a reading only in hiking mode — on a boat they are just noise.
- Hiking storm alarm takes the height out of the pressure trend (a 15 m walk down used to ring "pressure rising"); heights are weighted by GPS accuracy; the barograph says when the alarm pauses for lack of a GPS height.
- Fired storm alarms show as red dots on the pressure curve.

Fixed
- Logbook sometimes did not load right after an app update ("duplicate column", Sentry FLUTTER-W/V): app and background service upgraded the database at the same moment; the check from 2.7.0 was not enough.

### 2.7.0 — 2026-11-01

Heel & sea state (new)
- Heel gauge from the accelerometer: a card on the tracking screen (only while the phone is mounted) and a clinometer page with maximum and rolling (amplitude and period).
- Mounting is detected automatically (hand or pocket → "not mounted"). Upright reference from "Calibrate", or learned in harbour or from a tack.
- A calibration survives the phone being held still to read it; the gauge just pauses.
- Per log entry: heel (mean, max, side), rolling and roll period, in entry details, CSV export and the PDF logbook. An entry with nothing measured yet (shortly after the previous one, or after a restart) starts a measurement and gets its result filled in 20 s later.
- Switch in Settings → Advanced (battery: in the background only 20 s every 2 min during a trip).

Trip statistics
- Advanced statistics: heel, max heel and rolling lines, and tiles for mean/max heel and mean rolling, only for trips that measured them. Heel counts under way only (no anchor/harbour marker, at least 1.5 kn), otherwise every night at anchor halves the mean; the line breaks at anchor.
- Lines break after more than 2 h without a value instead of running diagonally across the night.
- The axis caption names the units of the lines shown (kn · °C · °).
- The whole "Advanced statistics" row expands it (only the small arrow did).
- PDF title page: mean heel under way (with max) and mean rolling / period.

Barograph, height, hiking
- A round trip with a change of height (train, car) is bridged: 12 h / 24 h trends keep running; the readings in between are marked orange and left out.
- Tap a reading for time, pressure and height; info on the orange legend.
- New height curve below the pressure (from pressure, anchored to GPS).
- Sailing / Hiking switch: hiking reads the sensor every minute.
- GPS height above sea level instead of the WGS84 ellipsoid (about 49 m difference in Switzerland), offline via a built-in geoid; phones that already report sea level are not corrected twice.
- Per log entry: GPS height with accuracy, speed and course accuracy (entry details, CSV).

Fixed
- New trip while the background service was already running (background barograph, weather alarm, anchor watch): GPS points were written into the previous trip and the entry counter continued there. The service now reads the active trip on every tick.
- Starting a trip logged a false "Course change" entry from the previous trip's course history; the history is now cleared at start.
- Logbook sometimes failed to load after an app update ("duplicate column", Sentry FLUTTER-S).
- Crash when setting/stopping the anchor alarm after leaving the screen (Sentry FLUTTER-R).
- "Moored?" question came back every 10–30 s while leaving slowly; now once per stop, then 2 h quiet at the same place.
- Tracking screen: the last card scrolls clear of the trip buttons.
- The first log entry after a background-service restart (app update, phone reboot) had no weather; it is now filled from the fetch right after it.
- Smart filter also scores measured pressure, heel, rolling and height; the PDF heel column header explains L/R.

### 2.6.0 — 2026-10-29

Barograph
- Current pressure in large type at the top, with the time of the reading and a trend arrow (1 h, 3 h once 3 h of history exist). The "i" button explains the cadence (sensor every 5 min, curve every 10 min).
- New "Record in background" switch: the barograph records without the weather alarm and without a trip.
- "Measured / Sea level" toggle: converts the reading to sea level by comparing with the weather service, and shows "measured at approx. X m".
- Weather-service line with a dashed forecast; fetched once on open, from storage when offline.
- Recording gaps shaded grey, changes of height (e.g. a drive) marked orange; trends no longer run across gaps and restart after a change of height. Every reading is a dot on the curve.
- Fixed: trends were missing in the 6 h tab and made up across gaps in the 2-day tab.
- Reloads on every open, "Retry" on errors, pull to refresh.

Weather alarm
- Uses the barograph history, so it starts with the curve already recorded.
- Names a change of height ("changed height by about 120 m, probably not weather") when GPS saw one, and the real time span ("in the last 10 min").
- Turning the alarm off keeps the barograph recording.

Background, battery, offline
- Barograph and alarm now record without a GPS fix (below deck, indoors).
- GPS requests time out (30 s in the app, then last known position; 45 s in the service, then a 5 min pause): "Stop" no longer hangs without sky view.
- The anchor tab only runs high-accuracy GPS while it is on screen, instead of from every app start, which saves battery.
- Online/offline status now follows signal changes everywhere.
- Cloud sync queues ploads them once thedevice is back online.
- Fixed "database istry FLUTTER-Q).
- Fixed the background service being reported as failed when it
  started slowly (Se

Other
- New trips are named "Trip 2026-10-29 11:11" 
- Trip statistics: barograph gaps shaded.

### 2.5.3 — 2026-10-28

Fix issue with MOB GPS not beeing stored

## Apps similar to NaviLog

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [YachtLog](https://appshunter.io/ios/app/yachtlog/id6787631220) | — | Free | Navigation |
| [Meridian Nav](https://appshunter.io/ios/app/meridian-nav/id6774504786) | — | $0.99 | Navigation |
| [Rubberduck: Sailing Log NMEA](https://appshunter.io/ios/app/rubberduck-sailing-log-nmea/id6770285345) | — | Free | Navigation |
| [BlueCruise: Sailing Log & GPS](https://appshunter.io/ios/app/bluecruise-sailing-log-and-gps/id6787195787) | — | Free | Navigation |
| [Sailing Log: Boat Logbook](https://appshunter.io/ios/app/sailing-log-boat-logbook/id6780126390) | — | Free | Navigation |
| [Hermes GFleet](https://appshunter.io/ios/app/hermes-gfleet/id1621723135) | — | Free | Navigation |

## More apps by Felix Bartschi

- [Clubhand](https://appshunter.io/ios/app/clubhand/id6816850012)

All apps by Felix Bartschi: https://appshunter.io/developer/6790909813

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-11-10.*