Module 4 - Channels & Frequencies

Channel 13 Is A Navigation-Safety Fallback, Not A Second Channel 16

Active recall

Section 9 of 9

Explain the main idea from channel 13 is a navigation-safety fallback, not a second channel 16 in your own words.

When another ship's MMSI is unknown, MCA small-craft guidance says to call by voice on Channel 16 using low power and move to an inter-ship channel once contact is made. If there is no response, try Channel 13, allocated in GMDSS for bridge-to-bridge communication.

That does not make Channel 13 a routine calling channel for marinas, friends, or long conversations. Use it for relevant bridge-to-bridge navigation communication and move extended traffic where appropriate.

Key points

  • Known MMSI: prefer an Individual DSC routine call and nominate an inter-ship channel.
  • Unknown MMSI: low-power voice call on Channel 16, then move off promptly.
  • No response: Channel 13 is the documented bridge-to-bridge fallback.

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