Module 9 - GMDSS & Safety Equipment
SART and AIS Locating
What you will learn
Choose and deploy on-scene locating aids according to the search unit that can detect them.
Radar SART and AIS-SART are both recognised locating means, but they transmit different signals and create different displays.
A radar SART listens in the 9.2–9.5 GHz band and responds when interrogated by compatible radar. The response appears as a distinctive sequence that changes as the rescue unit closes. Height and clear exposure improve the radio horizon, so deployment in a survival craft matters.
An AIS-SART transmits a locating signal that compatible AIS receivers can display. It is not the same as an ordinary vessel AIS transponder: its purpose, identity and indication are associated with search and rescue. An ordinary AIS target report does not replace the approved locating aid.
Selection must consider carriage requirements, route, likely search assets and approved equipment instructions. In use, activate and deploy the device correctly, preserve batteries, keep visual and radio watch and continue to follow rescue instructions.
| Aid | Detected by | Do not confuse with |
|---|---|---|
| Radar SART | Compatible 9.2–9.5 GHz search radar | A 406 MHz satellite beacon |
| AIS-SART | Compatible AIS receiving equipment | An ordinary vessel AIS report |
| EPIRB/PLB | Satellite alerting system plus homing support | The complete on-scene locating plan |
Match the transmitter to the search sensor
A liferaft crew sees a rescue vessel approaching but assumes its radar SART will appear as an AIS target.
1. Identify the aid
Confirm whether the carried unit is radar SART or AIS-SART.
2. Deploy correctly
Follow the device instructions and raise it as high and clear as practicable.
3. Keep communicating
Use available voice, light and visual signals rather than waiting passively for one display.
Sense check: A correctly operating transmitter still cannot appear on equipment that does not receive its signal type.
Common mistake or limitation
- Expecting a radar SART to create an ordinary AIS vessel symbol.
- Leaving the locating aid low or shielded when it can be deployed safely higher.
- Using 'SART' without distinguishing radar SART from AIS-SART.
Recap
- Radar SART responds to 9.2–9.5 GHz search radar.
- AIS-SART is displayed by compatible AIS equipment and is not ordinary vessel AIS.
- Correct identification, deployment and complementary watchkeeping matter.
Optional quick check
Section 6 of 10
Which receiver is intended to detect a radar SART?
Sources and factual review
Reviewed 20 August 2026 - Compass Revision editorial review.
Continue studying GMDSS & Safety Equipment
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