What Does Ship Speed Mean in Marine Radar?
Ship speed is one of the most critical data points to look at when tracking a vessel in real time. It tells you how fast a ship is moving and provides immediate information about its activity, navigation status, and operational behavior.
Understanding vessel speed is vital for maritime professionals, port authorities, logistics teams, and ship spotters because it helps them better understand vessel movement.
With Marine Radar: Vessel Tracker, a vessel’s speed is displayed using live AIS (Automatic Identification System) data, allowing users to monitor vessels globally in near real time, both near the coast and across open oceans.
What Is Ship Speed?
Ship speed refers to how fast a vessel is moving over the water, typically measured in knots (nautical miles per hour). This information is transmitted by the vessel’s AIS transponder and continuously updated as the ship moves.
In marine radar, a vessel’s speed helps users quickly determine whether a vessel is
- Actively sailing
- Slowing down
- Anchored or drifting
- Approaching or leaving a port
How Does Marine Radar Display Vessel Speed?
Marine Radar receives vessel speed data through AIS signals collected from:
- Terrestrial AIS receivers for coastal and port areas
- Satellite AIS networks for offshore and remote ocean coverage
Once received, this data is processed and displayed clearly in the vessel profile, alongside:
- Position
- Course and heading
- Navigational status
- Destination and ETA
- IMO and MMSI numbers
Typical Ship Speed Ranges
Understanding normal vessel speed ranges helps identify vessel behavior. By observing these ranges in Marine Radar, users can quickly understand what a vessel is doing without additional data.
- 0–1 knots: Anchored or moored (tied up)
- 1–5 knots: Moving, drifting, or waiting
- 10–15 knots: Cargo vessels underway
- 15–25 knots: Passenger ships and ferries
- Above 25 knots: High-speed craft
Why Is Ship Speed Important in Vessel Tracking?
1. Identifying Vessel Activity
Ship speed reveals whether a vessel is underway, approaching port, or stationary. Sudden speed changes may indicate:
Arrival or departure
Course adjustments
Mechanical issues
2. Supporting ETA Accuracy
Marine radar uses vessel speed as a key input to calculate the Estimated Time of Arrival (ETA). Speed changes directly impact voyage predictions.
3. Improving Port and Fleet Planning
Port operators and fleet managers track ship speeds to:
Manage berth availability
Reduce congestion
Optimize turnaround times
4. Safety Awareness
Unusual speed patterns can signal:
Restricted maneuverability (limited mobility)
Emergencies
Navigational risks
Ship Speed vs Course and Heading
Although ship speed indicates a vessel’s speed, it is most effective when viewed in conjunction with
- Course over ground (COG): Direction the vessel is actually traveling
- Heading: The direction the ship’s bow is pointing
Marine Radar displays all three together, offering a complete picture of vessel movement and navigation behavior.
What are the factors that affect a vessel's speed?
Marine Radar helps users observe how factors affect speed in real time and along historical routes. Several variables influence vessel speed, including
- Weather and sea conditions
- Traffic density
- Engine performance
- Port regulations
- Route planning decisions
Why Is Marine Radar Ideal for Monitoring Vessel Speed?
Marine Radar stands out because it offers:
- High-frequency AIS updates
- Global satellite AIS coverage
- Accurate vessel profiles linked to IMO and MMSI
- Interactive marine traffic maps
- Route playback for speed analysis over time
Conclusion
Ship speed is one of the most potent indicators in live vessel tracking. With Marine Radar, users can easily monitor ship speed, understand vessel behavior, and make informed decisions based on live AIS data.
A vessel’s speed, when paired with course, heading, and ETA, converts unprocessed tracking data into practical maritime intelligence.
Download Marine Radar: Vessel Tracker from the Google Play Store or App Store today and experience real-time ship tracking.
FAQs
What is ship speed measured in on marine radar?
Ship speed is measured in knots (nautical miles per hour).
How often is a ship’s speed updated?
Updates depend on AIS transmission frequency and signal coverage.
Can ship speed be inaccurate?
Temporary inaccuracies can occur due to signal delays or AIS reporting issues.
