RYA SRC GMDSS 4 — Questions and Answers
Question 1: What is the purpose of NAVTEX in the GMDSS framework?
- To provide voice distress communications for ships at sea
- To automatically broadcast navigational warnings, weather forecasts and MSI to ships (Correct answer)
- To track vessel positions using satellite technology
- To relay DSC distress alerts to rescue coordination centres
Correct answer: To automatically broadcast navigational warnings, weather forecasts and MSI to ships
NAVTEX is an automated telex broadcast system that delivers Maritime Safety Information (MSI), including navigational warnings and weather forecasts, directly to a shipboard printer or screen.
Question 2: On what frequency does international NAVTEX operate?
- 156.525 MHz
- 2182 kHz
- 518 kHz (Correct answer)
- 406 MHz
Correct answer: 518 kHz
International NAVTEX broadcasts are transmitted on 518 kHz in the MF band, receivable out to approximately 400 nautical miles from the coast station.
Question 3: What GMDSS sea area covers coastal waters typically within 20–50 nm of a shore-based DSC VHF coast station?
- Sea Area A4
- Sea Area A3
- Sea Area A2
- Sea Area A1 (Correct answer)
Correct answer: Sea Area A1
Sea Area A1 is defined as an area within radiotelephone coverage of at least one VHF coast station providing continuous DSC alerting, generally within about 20–50 nm of the coast.
Question 4: A Category 1 EPIRB is designed to activate in which way?
- Manually only, by the crew turning a switch
- Automatically when submerged to 1–4 metres, or manually (Correct answer)
- Only when triggered by a DSC distress alert
- By satellite command from the rescue coordination centre
Correct answer: Automatically when submerged to 1–4 metres, or manually
A Category 1 EPIRB is float-free and hydrostatic — it activates automatically when immersed in water at 1–4 metres depth, and can also be activated manually.
Question 5: On what frequency does a 406 MHz EPIRB transmit, and which system detects it?
- 121.5 MHz — detected by the NAVTEX network
- 406 MHz — detected by the Cospas-Sarsat satellite system (Correct answer)
- 156.8 MHz — detected by coast stations on Channel 16
- 518 kHz — detected by NAVTEX stations
Correct answer: 406 MHz — detected by the Cospas-Sarsat satellite system
Modern EPIRBs transmit on 406 MHz, which is monitored by the international Cospas-Sarsat low-earth-orbit satellite network for precise position fixing and vessel identification.
Question 6: What is a Search and Rescue Transponder (SART) and on which frequency does it operate?
- A satellite beacon transmitting on 406 MHz to pinpoint a distress position
- A radar transponder operating at 9 GHz that creates a series of blips on rescuers' radar screens (Correct answer)
- A DSC device that transmits the vessel's MMSI on Channel 70
- A handheld VHF radio set to Channel 16 for voice distress calls
Correct answer: A radar transponder operating at 9 GHz that creates a series of blips on rescuers' radar screens
A SART is a radar transponder operating at 9 GHz (X-band) that, when triggered by a rescuer's radar, generates a line of 12 blips extending from the SART's position on the radar display.
Question 7: At what height should a SART be held or mounted to maximise the radar detection range?
- At water level to avoid reflection interference
- As high as possible, ideally at least 1 metre above the waterline (Correct answer)
- Submerged to 0.5 metres to activate the hydrostatic release
- Inside the liferaft bag to protect it from weather
Correct answer: As high as possible, ideally at least 1 metre above the waterline
Raising a SART as high as possible — at least 1 metre above the waterline and ideally much higher — maximises the line-of-sight range at which a searching vessel's radar can detect it.
RYA SRC GMDSS 4
What is the purpose of NAVTEX in the GMDSS framework?