The channel and the band

Which channel does what

The marine VHF band is cut into numbered channels with assigned jobs. Three are the same everywhere: 16, 70 and 13. Most of the rest depend on where you are.

Key facts

The maritime VHF band runs from roughly 156 to 162 MHz and is divided into numbered channels by Appendix 18 of the ITU Radio Regulations.
Three channels are fixed worldwide: 16 for distress, safety and calling, 70 for DSC data only, and 13 for bridge-to-bridge navigational safety between ships.
Intership channels such as 06, 08, 72 and 77 are for ship-to-ship working. Channel 06 doubles as the on-scene channel for coordination with SAR aircraft.
Port operations and VTS commonly sit on channels like 09, 12 and 14, but the allocation is local: the same number can be the harbour master in one country and something else entirely in the next.
Channels 15 and 17 are limited to 1 W and used for on-board communications: deck to bridge, mooring stations, tank soundings.
AIS uses two dedicated channels at the top of the band (161.975 and 162.025 MHz). They carry data, not voice.
Before arrival, take the working channels from the port guide, the ALRS or the passage plan, not from memory of the previous port.

Channels worth knowing

Channel	MHz	What it is for
16	156.800	Distress, urgency, safety and calling; listening watch at sea
70	156.525	DSC digital alerts and calls only; never voice
13	156.650	Bridge-to-bridge navigational safety, ship to ship
06	156.300	Intership working; on-scene coordination with SAR aircraft
08	156.400	Intership working
72	156.625	Intership working
77	156.875	Intership working
09	156.450	Varies by country: often pilots or port operations
12	156.600	Commonly port operations and VTS (check locally)
14	156.700	Commonly port operations and VTS (check locally)
15	156.750	On-board communications, 1 W
17	156.850	On-board communications, 1 W
AIS 1	161.975	AIS data
AIS 2	162.025	AIS data

Watch out

Bridge-to-bridge calls on Channel 13 are commonly made on low power: you are talking to a ship you can see, and 25 W would carry the conversation to every bridge within thirty miles.

Where this comes from

ITU Radio Regulations, Appendix 18; local allocations: national radio authorities and the Admiralty List of Radio Signals.

This is not a legal text: when in doubt, the current wording of the Radio Regulations and the SMCP decides.

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