GMDSS Cheat Sheet 2026

The 30 highest-yield GMDSS facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. Where must a 406 MHz EPIRB be registered? → With the vessel's flag state administration or its designated authority
2. On which frequencies does a 406 MHz EPIRB transmit? → 406 MHz and 121.5 MHz
3. What is the homing frequency transmitted by an EPIRB to assist SAR aircraft and vessels? → 121.5 MHz
4. In Global Maritime Distress and Safety System, why is digital selective calling knowledge important for professional certification? → It demonstrates competence and ensures practitioners meet established standards
5. In the context of Global Maritime Distress and Safety System, what is the primary purpose of conducting a job hazard analysis related to navigation safety? → To identify potential risks before they cause incidents
6. You send a VHF-DSC Distress alert. What channel do you use for the follow-on voice transmission? → Ch-16
7. How does an AIS-SART differ from a traditional radar SART? → AIS-SARTs transmit their position as an AIS target visible on AIS-equipped displays
8. On what frequency band does a radar Search and Rescue Transponder (SART) operate? → 9 GHz (X-band)
9. In Global Maritime Distress and Safety System, what role does continuing education play in position reporting? → To keep professionals current with evolving standards, technologies, and best practices
10. What is a best practice in Global Maritime Distress and Safety System weather information? → A method or technique recognized as superior based on evidence and expert consensus
11. What is the purpose of a compliance training program in Global Maritime Distress and Safety System? → To educate personnel about applicable regulations and their responsibilities
12. What is the primary objective of weather information in Global Maritime Distress and Safety System? → To ensure competence and proficiency in core weather information concepts
13. What is the function of the hydrostatic release unit (HRU) fitted to a Category I EPIRB bracket? → It automatically releases and floats the EPIRB free when submerged to 1–4 meters depth
14. What action must a vessel take after receiving a MAYDAY relay from another vessel? → Acknowledge receipt and proceed to the distress area if able
15. How many times is MAYDAY spoken at the beginning of a distress call? → Three times
16. Which communication barrier is most likely to cause misunderstandings in Global Maritime Distress and Safety System? → Using technical jargon without considering the audience's knowledge level
17. In Global Maritime Distress and Safety System, why is equipment maintenance knowledge important for professional certification? → It demonstrates competence and ensures practitioners meet established standards
18. If the vessel is experiencing atmospheric interference with NAVTEX broadcasts, especially in the tropics, the GMDSS operator should: → Select one of the 8 HF MSI frequencies and set up the transceiver in FEC telex mode.
19. If the vessel is beyond the range of NAVTEX broadcasts and the Sat-C system fails, the GMDSS operator must: → Select an HF MSI frequency and FEC telex mode to receive MSI.
20. Which statement is NOT true regarding the COSPAS-SARSAT system? → May be used to transmit public correspondence.
21. What is the relationship between theory and practice in Global Maritime Distress and Safety System digital selective calling? → Theory provides the foundation and framework that guides effective practical application
22. Which frequency do Search and Rescue Transponders (SARTs) operate on? → 9 GHz (X-band radar)
23. In Global Maritime Distress and Safety System, which type of safety inspection involves a comprehensive review of all workplace areas? → General inspection covering all areas and conditions
24. What does a Category I EPIRB do that a Category II EPIRB does not? → Automatically activates and floats free when submerged to 1-4 meters
25. What is the relationship between theory and practice in Global Maritime Distress and Safety System weather information? → Theory provides the foundation and framework that guides effective practical application
26. In Global Maritime Distress and Safety System, when communicating complex information, which strategy is most effective? → Breaking information into smaller, manageable segments
27. What information is encoded in a 406 MHz EPIRB's distress transmission? → A unique 15-digit identification code linked to the vessel and owner
28. After a false GMDSS distress alert is transmitted, what must the vessel do? → Immediately cancel the alert on DSC and contact the RCC on voice radio
29. AAis (Aeronautical) emergency frequency 121.5 MHz is notable in GMDSS because: → It is the EPIRB homing frequency used by SAR aircraft
30. Under GMDSS, what is required to be posted near the main radio installation? → Radio operator license and distress/safety communication procedures