RYA SRC MMSI Numbers 2 — Questions and Answers
Question 1: What is the MMSI format for a life-saving appliance (e.g., EPIRB or life raft)?
- 97XXXXXXXX (10 digits starting with 97) (Correct answer)
- 9XXXXXXXX (9 digits starting with 9)
- 00XXXXXXX (9 digits starting with 00)
- Same format as the parent vessel
Correct answer: 97XXXXXXXX (10 digits starting with 97)
MMSIs for life-saving appliances such as EPIRBs and SARTs use a 10-digit format beginning with 97, distinguishing them from vessel MMSIs (9 digits) and coast station MMSIs.
Question 2: What does a group MMSI allow?
- A fleet manager to call multiple vessels simultaneously (Correct answer)
- A vessel to call the coastguard directly
- A vessel to receive weather broadcasts
- Two vessels to share a single MMSI
Correct answer: A fleet manager to call multiple vessels simultaneously
A group MMSI allows fleet operators to make a single DSC call that is received by all vessels sharing that group MMSI, enabling simultaneous contact with an entire fleet rather than individual calls.
Question 3: What is the all-ships MMSI used for DSC all-ships calls?
- 999999999 (Correct answer)
- 000000000
- 123456789
- 111111111
Correct answer: 999999999
The all-ships MMSI is 999999999 (nine nines). Using this MMSI in a DSC call transmits to all vessels within range, similar to an all-ships broadcast on Channel 16.
Question 4: Should an MMSI be programmed into a VHF radio before or after purchase?
- Before use — it must be programmed before the radio is operated (Correct answer)
- After the first voyage
- Only if the radio is installed professionally
- MMSIs do not need to be programmed into the radio
Correct answer: Before use — it must be programmed before the radio is operated
The MMSI must be programmed into the DSC radio before the radio is used. Operating a DSC radio without a programmed MMSI means it cannot function correctly for distress alerting or DSC calls.
Question 5: What happens if two vessels share the same MMSI?
- DSC calls and distress alerts become unreliable and coast stations cannot identify the correct vessel (Correct answer)
- Both vessels receive all calls to that MMSI
- The vessels must operate on different channels
- Ofcom automatically detects and resolves the conflict
Correct answer: DSC calls and distress alerts become unreliable and coast stations cannot identify the correct vessel
If two vessels share an MMSI, any DSC distress alert will identify the wrong vessel to rescuers, creating potentially fatal confusion. Coast station databases will show incorrect vessel details, seriously compromising SAR effectiveness.
Question 6: Can a hand-held DSC VHF radio have a different MMSI to the fixed radio on the same vessel?
- Yes, each DSC radio requires its own registered MMSI (Correct answer)
- No, all radios on the same vessel must share the MMSI
- Yes, but only the fixed radio MMSI is used for distress
- No, only one DSC radio is permitted per vessel
Correct answer: Yes, each DSC radio requires its own registered MMSI
Each DSC-capable radio requires its own registered MMSI. A vessel may have multiple DSC radios (fixed and hand-held) each with different MMSIs, all of which should be registered with Ofcom.
RYA SRC MMSI Numbers 2
What is the MMSI format for a life-saving appliance (e.g., EPIRB or life raft)?