Last updated: 26 October 2026 · By Steve Joury, cargo trip advisor at CargoHolidays
Cargo ships navigate using satellite positioning, electronic charts, radar, AIS and gyrocompasses, with officers on watch 24 hours a day following a detailed passage plan and international collision rules. Near ports, local pilots come aboard. Here’s how it all fits together.
Key facts at a glance
How do cargo ships navigate across oceans with such precision? It starts before departure with a passage plan prepared by the second officer: every waypoint, depth, hazard, reporting point and tidal window from one berth to the next. At sea, a navigating officer stands watch on the bridge around the clock, monitoring the plan, traffic and weather.
| Equipment | What it does |
|---|---|
| GNSS (GPS and others) | Satellite position, speed and time |
| ECDIS | Electronic charts with the route, depths and alarms |
| Radar (X- and S-band) | Detects ships, coastlines, buoys and rain, day or night |
| AIS | Exchanges identity, position and course with other ships |
| Gyrocompass and magnetic compass | Accurate heading, with a magnetic backup |
| Autopilot | Steers a set course in open water |
| Echo sounder | Measures water depth under the keel |
| GMDSS radios | Distress and safety communications |
Learn how anyone can follow ships using AIS in Cómo seguir el recorrido de un barco.
Ships follow the International Regulations for Preventing Collisions at Sea (COLREGs). They set out who gives way, lights and sound signals, and how to behave in narrow channels and traffic separation schemes such as the Dover Strait. Officers watch for other ships constantly and take early, obvious action to avoid close encounters.
Ships receive detailed forecasts and often professional routing advice to avoid storms and save fuel. A slightly longer route around a gale can be faster and safer. Read ¿Qué le ocurre a un buque de carga durante una tormenta? y Explicación del parte meteorológico marítimo.
Approaching most ports, a local pilot boards by ladder from a pilot boat and advises the captain through the channel, then tugs help the ship berth. The captain remains in command. Passengers often watch the pilot boarding – it’s impressive seamanship, especially in a swell.
With satellite positioning, electronic charts, radar, AIS and gyrocompasses, following a detailed passage plan.
Most large ships now use ECDIS electronic charts, with backup arrangements required.
Usually the autopilot at sea, supervised by the officer on watch; a helmsman steers by hand in ports and channels.
The international rules for preventing collisions at sea – the ‘rules of the road’.
Local pilots know the port’s channels, currents and hazards and advise the captain on the approach.
Visit a ship’s bridge
Freighter passengers often spend hours on the bridge with the officers. Find your voyage.
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