Which channel?

There are 57 VHF channels available in the International Maritime Mobile Service, numbered 1‑28 and 60‑88.  They have different allocated uses, including inter-ship communication, port operations and ship movement and some channels are allocated for more than one use.  Some channels use simplex operation (single frequency) and this applies to all intership channels, while some of the port operations channels use duplex operation (different frequencies for transmission in each direction).

There are also the private channels (29-59) of the UK Maritime Mobile Service, which are licensed to specific commercial users on application.  These are used for communication between private coastal radio stations and ships, for commercial purposes, and do not concern us here, except for Channel 37 (Channel M), which is allocated as a Marina channel, as are Channel M2 (used for yacht race control) and international Channel 80 (a duplex channel).  M1 and M2 are for use by pleasure craft only, for communication between vessels and marinas or yacht clubs and none of these three marina channels may be used for intership communication.  Use of channels M1 and M2 is covered by your ship radio licence, in addition to the international channels.

For vessels fitted with GMDSS compatible equipment, Channel 70 is the calling and distress channel.  This channel must only be used for digital selective calling and never for oral communication.  Channel 16 is the calling and distress channel for voice communication and is also used as the working channel for distress calls initiated on Channel 70.  It must only be used for distress, urgency or safety working or for establishing contact, after which you must transfer to a working channel.  In most cases, on inland waterways, you should call first on the relevant working frequency, not Channel 16.  This will all be covered in your RYA course.

You will be concerned mainly with ‘inter-ship communication’, ‘port operations’ or ‘marina’ channels.  Locks, bridges and port control stations all operate on ‘port operations’ channels and those relevant to UK inland freight waterways are listed in Appendix B, which also includes some isolated waterways accessible to trailed boats.  This makes it clear which channels you should use for intership working or calling up locks or bridges.  Marinas on these waterways with marine VHF radio and visitor facilities are listed in Appendix C.

Note that you should maintain a listening watch on the appropriate port operations channel for the waterway, which may be different from the channel for locks.  For example, on the Thames in London you must listen on Channel 14 but you will need to change to Channel 80 to call Limehouse Lock.  Similarly, travelling from Hull to York, you must listen on Channel 12 (VTS Humber) as far as the Humber Bridge; you should then change to Channel 15 for the Ouse up to Goole (Hook) Railway Bridge, then to Channel 9 up to Naburn, upstream of which convention dictates that you listen on Channel 6.  However, to call Barmby, Selby or Naburn locks you will need to change to Channel 74 or to call Goole Docks you will need to change to channel 14. 

Relevant ‘listening watch’ channels are listed in Appendix B.  These are important, as commercial vessels will expect you to listen on these channels and will use them if they call you.  By monitoring radio traffic on these channels you will also learn what large vessels are moving and where.  To contact another vessel on these waterways, try calling first on the ‘listening watch’ channel, then try Channel 74 if on a CRT 1 waterway, and only use Channel 16 if this does not achieve a response.  In some cases it may be useful to call a group of vessels, for example, on the Trent north of Keadby a call to ‘Trent Ships’ on Channel 15 may be useful if you want to ask if there is any movement occurring on the lower reaches.

You should not forget that absence of a response to your call does NOT mean that the route is clear for you.  Your radio may not be working, your antenna may not be high enough for the location, you may be calling on the wrong channel or the other skipper may not have heard or may have heard but not replied.  Always proceed with care and keep a good look-out for larger vessels.  At some locations with restricted visibility, it is common practice to announce your approach and direction of travel on the ‘listening watch’ channel.  You will not necessarily get a reply but other craft may have received your message and adjusted their progress to avoid meeting you at an awkward place.

Channel 74 deserves particular mention.  This is a port operations channel allocated to the Canal and River Trust’s locks and bridges listed in Appendix B.  Contrary to widespread rumour, it is not a private Canal and River Trust channel and is also allocated to various other port operators in the UK.  Channel 74 is not allocated for general inter-ship use but, within a port, intership communication on ship movements and safety should be made on the port frequency 2.  This is where some confusion arises – where are the limits of the port, when we are considering a whole network of inland waterways with dispersed locks fitted with radio?  In practice, you should keep a listening watch on Channel 74 and use this channel for initial intership contact on the following CRT freight waterways.

Aire & Calder Navigation Weaver
Sheffield & South Yorkshire Navigation (below Rotherham) Severn and G&S Canal
Trent (upstream of Cromwell Lock) Crinan Canal
Lea (Lee) Caledonian Canal



However, note the different channels that you should monitor on the Ouse, Trent, Humber, Thames and Severn tideways.  Most modern VHF sets now have a scan facility, so you can monitor two or more channels simultaneously.  This can be particularly useful (e.g. to listen on both Channel 9 and Channel 74 on the upper Yorkshire Ouse tideway), but you must make sure that you know how to lock on to the right channel before replying.

Under the GMDSS system, Channel 13 is now the internationally agreed channel for ship to ship communication on navigational safety matters and ships are encouraged to maintain a listening watch on this channel (as well as Channels 70 and 16) outside areas covered by port operations or VTS.  However, Channel 13 should not be used for inter-ship communication on anything other than navigational safety matters or port operations.

You should not use the VHF radio for long chats about nothing in particular – it is in fact forbidden to make ‘unnecessary transmissions or transmit superfluous signals’.  However, there are conventions as to what is tolerated on various channels.  Intership communications that are not strictly relevant to vessel navigation should be kept off Channel 13 and off channels that are allocated to local port operations.  Similarly, you should avoid channels that have other regular uses; for example, Channel 9 is frequently used for communication between ships and tugs.  In the UK, you should use Channels 6, 8, 72 or 77 for general inter‑ship communications.  If you are in a group sailing together, it is useful to agree in advance which channel you will use for communication within the convoy.

In all cases, use the minimum power that will achieve the necessary range – there is no point in transmitting 25 Watts of power to a vessel 100 metres away, when 1 Watt will do.  Using low power minimises interference with other users.

See also:

Buying a Boat
Hiring a Boat
Living Afloat

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