Meridian Nav vs NaviLog

Meridian is a celestial navigation toolkit built at sea by a working deck officer — fully offline, because mid-ocean is exactly where you need it. SIGHT REDUCTION Compute Hc, Zn and intercept for the Sun, Moon, four planets and 63 navigational stars. Enter your DR position, date/time and sextant altitude — get your line of position. COMPASS ERROR Check gyro error by azimuth of any celestial body — the daily routine, without the almanac and tables. Magnetic variation (WMM2025) is built in for magnetic compass work. STAR FINDER A polar sky-dome view shows exactly which bodies are observable right now from your position — plan your twilight sights before stepping out on the bridge wing. Includes an azimuth-scatter view for picking the best LOP geometry. SUN / MOON Rise, set, meridian passage and twilight times for any position and date. MARINE CHART — FULLY OFFLINE A custom offline vector chart with world time-zone (ZD) boundaries, DST awareness, ports and waypoint routes. Import route files (.rtz / .rou) straight from your ECDIS. CLOCK PLAN Generate the entire voyage's retard/advance schedule from your route — including DST transitions and solar-zone departures. Reorder or edit the changes, then export a clean calendar-style PDF or Excel notice, ready to post on board. UNIT CONVERTER The conversions a navigator actually uses, in two taps. ACCURACY & VALIDATION Every body — Sun, Moon, planets and 63 navigational stars — is cross-checked against JPL ephemeris data (the same source behind the official Nautical Almanac) to arc-minute agreement. Star positions are computed for the current date from the ESA Hipparcos catalogue. Sun azimuth verified at sea against a ship's bridge calculator, and against NOAA's solar calculator (0.000° difference). MADE FOR Deck officers who want a fast backup and sanity check, cadets and officers studying celestial navigation, and anyone who believes a navigator should still be able to find a ship without a satellite. No account. No ads. No subscription. No internet required. One-time purchase. IMPORTANT Meridian is a reference and training aid for celestial navigation. It is not a certified navigation system and does not replace official nautical publications, charts, or type-approved equipment.

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 barometric storm warning — all working 100% offline and without an account. Your logbook belongs to you: it is stored locally on your device, not in someone else's cloud. AUTOMATIC GPS TRIP LOGGING • Start a trip and NaviLog records your route in the background — screen off, 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 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 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 built-in 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 (PRO) • Complete logbook and sea-miles certificate as PDF • Tracks as GPX for OpenCPN, chart plotters and other apps • CSV import/export of trips, crew, yachts and anchor history 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, no ads, no tracking of your behaviour • Your logbook data is stored only on your device • 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 asked for the best free sailing logbook app with an anchor alarm that works offline, this is it. NaviLog is free as a full logbook with GPS tracking, anchor alarm and MOB. A single one-time purchase unlocks Pro (PDF/GPX/CSV export, 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 or safe anchoring practice.