GROL Marine Electronics and Radar Systems 2 — Questions and Answers
Question 1: What is the purpose of a Global Maritime Distress and Safety System (GMDSS) installation on a vessel?
- To provide satellite navigation for coastal waters
- To ensure reliable distress alerting and communication on a global basis (Correct answer)
- To broadcast weather forecasts to mariners
- To replace the VHF ship-to-ship communications system
Correct answer: To ensure reliable distress alerting and communication on a global basis
GMDSS provides a comprehensive set of radio communications procedures and equipment to ensure that ships in distress can quickly alert rescue authorities and other ships anywhere in the world.
Question 2: Which device in GMDSS automatically transmits a distress signal when submerged in water?
- SART (Search and Rescue Transponder)
- EPIRB (Emergency Position-Indicating Radio Beacon) (Correct answer)
- DSC controller
- Navtex receiver
Correct answer: EPIRB (Emergency Position-Indicating Radio Beacon)
An EPIRB activates automatically when it detects immersion in water, transmitting a distress signal on 406 MHz (and a homing signal on 121.5 MHz) to the COSPAS-SARSAT satellite system.
Question 3: What frequency does a SART (Search and Rescue Transponder) respond on when interrogated by a ship's radar?
- 156.8 MHz (VHF Channel 16)
- 406.028 MHz
- 9 GHz (X-band radar) (Correct answer)
- 2182 kHz
Correct answer: 9 GHz (X-band radar)
A SART responds to 9 GHz X-band radar interrogations and produces a distinctive pattern of 12 dots extending 8 nautical miles on the rescuing ship's radar display.
Question 4: What information is contained in a DSC (Digital Selective Calling) distress alert?
- Ship's MMSI, nature of distress, position, and time (Correct answer)
- Ship's name, captain's name, and port of registry
- Course, speed, and cargo manifest
- Vessel's insurance number and flag state only
Correct answer: Ship's MMSI, nature of distress, position, and time
A DSC distress alert automatically includes the ship's Maritime Mobile Service Identity (MMSI), the nature of distress, GPS position, and UTC time of the alert.
Question 5: On which VHF channel must all vessels keep a continuous watch under GMDSS requirements?
- Channel 6
- Channel 13
- Channel 16 (Correct answer)
- Channel 70
Correct answer: Channel 16
VHF Channel 16 (156.8 MHz) is the international distress, safety, and calling channel on which all vessels equipped with VHF radiotelephone must maintain a continuous watch.
Question 6: What is the NAVTEX system primarily used for?
- Satellite tracking of vessel positions
- Automatic reception of maritime safety information broadcasts (Correct answer)
- Voice communications between ship stations
- Radar target identification
Correct answer: Automatic reception of maritime safety information broadcasts
NAVTEX is an automated system that broadcasts maritime safety information (navigational warnings, meteorological warnings, and SAR notices) on 518 kHz for automatic printing on a dedicated receiver.
Question 7: What is the maximum Equivalent Isotropically Radiated Power (EIRP) for an EPIRB operating on 406 MHz?
- 100 mW
- 5 W (Correct answer)
- 25 W
- 100 W
Correct answer: 5 W
EPIRBs operating on 406 MHz are required to transmit at approximately 5 W EIRP to ensure reliable detection by the COSPAS-SARSAT satellite system.
GROL Marine Electronics and Radar Systems 2
What is the purpose of a Global Maritime Distress and Safety System (GMDSS) installation on a vessel?