EPIRB and SART Activation During an Abandonment Drill
During an abandonment drill on a 90 m offshore supply vessel in sea area A1/A2, the crew activate a float-free EPIRB and a SART. The EPIRB is a 406 MHz model with a 121.5 MHz homing transmitter. The SART is a 9 GHz radar SART. The drill takes place in daylight with the vessel at anchor. The EPIRB is tested using its self-test function, which shows a green light and a short flash. The SART is switched on and placed in the liferaft; the vessel's radar is on and shows no SART response. The crew also have an AIS-SART on board but it is not activated. The EPIRB's battery expiry date is 18 months away.
1. Explain the purpose of the EPIRB self-test and what the green light and short flash indicate.
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The EPIRB self-test checks the beacon's internal circuitry, battery condition and, in many models, the 406 MHz transmitter and the 121.5 MHz homing transmitter at low power without transmitting a distress alert. A green light and a short flash typically indicate that the self-test passed and that the beacon is ready for operation. It does not confirm that the beacon will be received by the COSPAS-SARSAT system, nor does it confirm the battery's capacity under load. The test should be carried out in accordance with the manufacturer's instructions, usually monthly, and the result recorded. The battery expiry date should be noted and the battery replaced before expiry.
2. Why might the radar SART not appear on the vessel's radar, and what should be checked?
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A 9 GHz radar SART responds to a radar signal by transmitting a series of pulses that appear as a line of dots on the radar display. If no response is seen, possible reasons include: the SART is not switched on or is in standby; the SART is not within line of sight of the radar antenna (for example, screened by the liferaft canopy or the vessel's structure); the radar is not transmitting on the correct frequency or is in a mode that suppresses the response; the radar's gain or tuning is set incorrectly; the SART battery is depleted; or the SART is faulty. Check that the SART is switched on and its indicator shows it is operating, that it is mounted at least 1 m above sea level and not screened, that the radar is on and tuned, and that the range scale is appropriate. The SART should be tested in accordance with the manufacturer's instructions, and the AIS-SART can be used as an alternative.
3. What are the differences between a radar SART and an AIS-SART, and when would you use each?
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A radar SART operates in the 9 GHz band and responds to a radar interrogation by transmitting a characteristic response that appears on the radar display as a line of dots. It requires a radar to be within range and line of sight, and it does not provide identity or position data. An AIS-SART transmits an AIS message that is received by AIS-equipped vessels and shore stations, providing identity and position, and can be detected at longer ranges. The AIS-SART is generally preferred where AIS coverage is good, while the radar SART is useful where radar is the primary detection means. Both should be carried as required by the vessel's GMDSS equipment, and the choice depends on the circumstances and the equipment available. In a drill, both should be tested and their operation understood.