NavChrono — Ship Voyage ETA, Distance & Passage Planner

Offline-capable passage planning, marine voyage calculation, ship ETA estimation, and IMO planning checklists for deck officers, ship masters, navigators, and maritime academy cadets.

Dedicated Maritime Navigation & Voyage Calculation Tools

  • Ship Voyage & ETA Calculator: Computes high-precision vessel steaming duration across nautical time zones and the International Date Line (IDL), eliminating zone description (ZD) and ±24h day-shift errors.
  • Port to Port Sea Distance Calculator & Distance Table: Instant maritime distance calculations across 337 major commercial seaports, routing via Suez Canal, Panama Canal, Strait of Malacca, Strait of Gibraltar, Bab el-Mandeb, and Cape of Good Hope.
  • Under Keel Clearance (UKC) & Ship Squat Calculator: Computes empirical shallow water squat estimates (Barrass & Millward formulas), dynamic draft, and net under keel clearance margins for passage planning appraisal.
  • RTZ & GPX Route Exchange Exporter (IEC 61174 Format): Exports draft passage waypoints to IEC 61174 Edition 4 .RTZ XML, .GPX, and .CSV formats for import and verification on external bridge chart systems.
  • Passage Planning & Chart Plotter: Great Circle (orthodromic) and Rhumb Line (loxodromic) track calculation with optional online OpenSeaMap seamarks, NOAA ENC layers, and Esri/GEBCO bathymetry.
  • Major Commercial Sea Routes Library: Pre-calculated sea distances, transit times at 14 & 18 knots, fuel estimates, and canal comparisons for major shipping lanes.
  • Maritime Calculation Guides & Worked Examples: In-depth mathematical formulations for ship squat, UKC, bunker consumption & economical speed, Great Circle sailing, and IMO Res. A.893(21) planning.
  • Offline-Capable Core & Night Watch Display Modes: Core calculators, 337-port directory, and distance routing are cached via Service Worker for offline use at sea (live chart tile overlays require an internet connection). Features Deep Navy, High-Contrast Daylight, and Red Night-Vision mode (low-glare red palette for dark-adapted night watch).

Major Maritime Trade Lanes & Benchmark Distances

Singapore → Rotterdam

Via Suez Canal: 8,288 NM | Via Cape of Good Hope: 11,725 NM

Shanghai → Los Angeles / Long Beach

North Pacific Great Circle: ~5,740 NM (IDL Retard Date Adjustment)

Cartagena (Colombia) → Yokohama (Japan)

Via Panama Canal: ~8,000 NM @ 16 kn = 20d 20h (Date Advance)

Houston / US Gulf → Rotterdam

North Atlantic Corridor: 4,990 NM | Transit: ~13 days @ 16 kn

Who Uses NavChrono

NavChrono is engineered for commercial watchkeeping officers (2nd Mates, Chief Officers), Master Mariners, marine superintendents, port captains, and maritime academy students requiring fast, reliable voyage calculation and passage planning aids on workstations, laptops, tablets, and mobile phones.

Frequently Asked Questions

How does NavChrono handle International Date Line crossings?

NavChrono normalizes the departure local time to UTC using exact DST-aware offsets from the IANA timezone database (alongside textbook Nautical Zone Description ZD = +West / -East and whole-hour ship clock tracking at sea), adds steaming duration, and converts arrival UTC to destination Local Time, correcting automatically across the 180th meridian.

How to export a printable IMO passage plan dossier?

Under Passage Planning and the IMO Audit tab, bridge officers can review the 4 stages of passage planning (Appraisal, Planning, Execution, Monitoring under IMO Resolution A.893(21) and SOLAS Chapter V Regulation 34) and export an A4 planning dossier complete with waypoint breakdown, speed/fuel matrix, UKC appraisal, and officer review blocks.

Which features work offline vs. requiring internet?

NavChrono's Progressive Web App (PWA) caches the core ETA calculator, 337-port directory, distance routing graph, UKC/Squat calculator, and RTZ/GPX exporter for offline operation at sea. Live third-party chart tile overlays (OpenSeaMap, NOAA ENC, Esri/GEBCO, OpenStreetMap) and Google AdSense require an active internet connection.