What are the Dualwatch and Tri-Watch functions on a marine VHF radio?
Dualwatch and Tri-Watch are important features on marine VHF radios that allow you to monitor multiple channels simultaneously. While both functions relate to channel scanning, they operate slightly differently. In this article we explain the differences and importance to anyone using a marine VHF radio on the water.
Dualwatch
The Dualwatch function allows the radio to periodically monitor
Channel 16 (the international distress frequency) while you are actively communicating or listening on another selected channel. The radio will interrupt the current channel briefly at set intervals to check for activity on Channel 16. If a signal is detected on Channel 16, the radio will switch to that channel, ensuring you don't miss any distress calls or important safety announcements. Once the Channel 16 check is complete (or if there's no activity), the radio will return to your original selected channel. This is an important feature as Channel 16 is the primary channel for distress calls, safety broadcasts and initial contact with other vessels.
Tri-Watch
Tri-Watch allows the radio to monitor two channels in addition to your currently selected channel. Typically, this includes Channel 16 and another channel you have chosen. So, you might be communicating on a working channel (e.g., a channel used for coordinating with a marina or other boats in your group) while simultaneously monitoring Channel 16 for distress calls and a designated weather channel for up-to-date forecasts. Like Dualwatch, Tri-Watch regularly scans these channels, prioritising Channel 16.
In the UK and for Icom radios purchased from authorised UK dealers, Channel 37a (UK M1) is typically set as a default on Triwatch.
This can be changed in the radio's settings. This channel is specifically designated for club and marina use. However, it's important to note that radios sourced from overseas markets may not have this channel enabled. Also, some newer radios might display 37A as 1037, due to changes in the channel plan, but they function the same.
In Summary
Both Dualwatch and Tri-Watch are useful in many scenarios at sea such as in a sailing regatta where you could use Tri-Watch to monitor the race committee's channel for instructions, Channel 16 for safety calls and a local weather channel for updates. While cruising you might use Dualwatch to listen to your preferred channel while keeping a watchful ear on Channel 16 for any emergencies. While fishing you can communicate with other fishing vessels on a designated channel and use Dualwatch or Tri-Watch to maintain awareness of safety calls on Channel 16.
For more Information about our Radios
Using Dualwatch and Tri-Watch you can significantly improve your safety and communication effectiveness while on the water. For information about our range of Icom marine VHF products which feature both Dualwatch and Tri-Watch please visit the
marine VHF radio pages on our website.
