Voyage and offline navigation
Build routes and waypoints, follow passage progress, record tracks and prepare supported regional or harbor-detail map packs before coverage drops.
MARITIME OPERATIONS • ANDROID
One focused workspace for the work between berth and bridge.
CaptainCalc brings professional tides and UKC evidence, voyage planning, GMDSS preparation, stability and loading workflows, celestial navigation, bridge calculators and operational records into one captain-made Android app.
- Signed source-aware tide and current evidence
- Offline-first professional tools and map packs
- Deterministic calculations with explicit safety boundaries
Freemium keeps essential online tools available with ads. Premium removes ads, raises limits and unlocks the complete offline professional workspace.
Who it is forBridge officers, chief officers, ship masters, maritime students and cadets.
What it coversVoyage, tides, GMDSS, stability, cargo, celestial navigation and records.
Why offline mattersPrepared tools and installed data remain useful when connectivity drops.
A complete maritime workspace
Not a loose collection of calculators. CaptainCalc keeps vessel, voyage, source and record context visible from input to export.
Tides, currents and UKC
Work with signed FES predictions, NOAA events and available currents. Datum, source, confidence, tide, squat and safety margins stay explicit.
GMDSS decision support
Prepare DSC distress, urgency and safety worksheets, readiness checks, radio-log records and source-backed MSI/NAVTEX review—without transmitting or controlling radio equipment.
Stability, draft, cargo and tanks
Support six-draft surveys, hydrostatic interpolation, loading conditions, stability criteria, cargo planning, tank soundings and free-surface checks.
Celestial and bridge tools
Reduce sun, moon, star and planet sights; build fixes; identify bodies; and use ETA, CPA/TCPA, set and drift, fuel and squat calculators.
Audit-ready history and exports
Keep voyage and calculation records together and export supported PDF, CSV, GPX and KML outputs with operational context.
VOYAGE
Voyage planning, tracking and maps
Voyages, templates, routes, waypoints, port calls, live progress, track recording, installed offline map packs and supported PDF/CSV/GPX/KML exports.
TIDES & UKC
Professional tides, currents and UKC
Signed global FES predictions, NOAA high/low-water events, available current sources, visible datum and confidence, point UKC, route UKC, squat and operational safety margins.
GMDSS
Preparation, readiness and radio records
DSC distress/urgency/safety worksheets, equipment readiness, authorized radio logs, station directory and source-backed MSI/NAVTEX review. No transmission or radio control.
STABILITY
Draft survey and ship stability
Six-draft correction, hydrostatic interpolation, load cases, GM/GZ evidence, dynamic downflooding boundaries, criteria checks and explicit approved-source provenance.
Cargo, holds, tanks and FSM
Cargo planning, hold capacity, tank calibration and soundings, density/temperature corrections, free-surface moment verification and condition-aware loading context.
CELESTIAL
Almanac-grade celestial navigation
Sun, moon, planet and star observations, sight correction and reduction, lines of position, fixes, noon sights, body identification and planning tools.
Fast navigation calculators
ETA, TTG and fuel, rhumb line, great circle, CPA/TCPA, set and drift, compass error, amplitude/azimuth, squat/UKC and other routine bridge calculations.
Evidence, reliability and clear limits
Source visibility
Professional tide and GMDSS workflows preserve datum, source, verification and confidence evidence instead of hiding it behind a single number.
Offline continuity
Core calculations and installed content remain useful when shipboard connectivity is weak, expensive or unavailable.
Captain-owned data
Vessel, voyage, stability and calculation records remain local. Optional Premium cloud backup is encrypted snapshot restore—not live sync.
Safety boundaries
CaptainCalc is decision support. It never replaces approved stability data, loading computers, ECDIS, official publications, procedures or professional judgment.
CONTINUITY
Prepare before connectivity drops
Optional encrypted snapshots with up to 10 restore points, same-account recovery and up to 30 days of retrieval after Premium ends. Backup is not live synchronization.
Offline continuity
Core calculations and installed content remain useful when shipboard connectivity is weak, expensive or unavailable.
RECORDS
Keep operational context with the result
Records, exports and references
Voyage, stability, draft, tank and calculation history with supported export formats plus COLREG rules, sound signals, IALA and maritime reference material.
Choose the access level that fits the voyage
Freemium
- Essential tools while online
- Ad-supported access
- Saved records remain available
- No advertised free trial
Premium
- No ads and higher limits
- Complete professional suite
- Offline access and installed data
- Optional encrypted backup: 10 points, 30-day post-Premium retrieval, no live sync
CaptainCalc is decision support. It never replaces approved stability data, loading computers, ECDIS, official publications, procedures or professional judgment.