VHF Radio Use

Written by barrington

When you want to communicate with someone today, you would likely reach for your ever-present mobile phone. But in marine safety circles, there is a concern the reliance on mobile phones is causing many boaters to overlook one of the most useful safety features aboard your boat — the common VHF radio. Conceptually, VHF radios haven’t changed much in the last 40 years — a few dials, a few buttons and a microphone connected by a spiral cord. This may lead some, especially young boaters, to think of them as old fashioned or outdated. But VHF marine radios and the rescue network to which they are connected have modernized and are as relevant and useful as ever.

Benefits of Use

One of the most beneficial features of VHF radio is in accident avoidance, the ability to communicate with other boats. Especially with the increased use of AIS (Automated Identification System) you may know the name of a vessel you are about to encounter, but you certainly couldn’t call them on your mobile phone. The ability to communicate your intentions or to know the other vessel’s intentions is helpful in maintaining safe distances between passing or crossing vessels. Calling another vessel on the appropriate VHF channel is the best way to communicate boat to boat. Channel 16 is the universal hailing channel that all vessels equipped with a VHF radio are required to monitor. Channel 13 is used for conversations between commercial vessels and, by law, should be monitored by all vessels over 65 feet in length. If you want to negotiate a passing situation with a tug boat or container ship, channel 13 is the channel you would use to contact them. Channel 13 and, in some states, channel 9 are also used for calling bridge and lock tenders to request openings.

Channel Use and Etiquette

There is increasing misuse of VHF radios. A few things you can do to keep the airways quieter and available for their intended purpose are, never request a radio check on channel 16. Yes it’s important to know your radio is working, but calling for a radio check on channel 16 prevents the use of the channel for hailing and emergency callers. Seatow, the vessel towing and assistance company offers automated radio checks in many areas. The system uses VHF channels 24, 25, 26, 27, 28 and 84. Contact the local Seatow franchise for the proper channel in your area. Upon transmitting and releasing the mic, the system will replay your transmission, letting you hear how you sound. Another way to reduce traffic on the VHF is to switch your power setting to low when calling another boat or a marina near you. While it’s been stated here and by numerous other marine industry professionals that the mobile phone should not be a substitute for the VHF radio, this is largely as it relates to emergency and rescue calls. There is clearly a place for mobile phone use when calling a marina to obtain information in preparation for arriving. These conversations do not need to be public and help keep the airways clear for more important transmissions. Radio use with the dock personnel for final docking instructions can then be kept to a minimum.

Safety at Sea

One of the most valuable safety features which has been available in fixed mounted VHF radios for a numbers of years, is the single-button distress call feature, called Digital Selective Calling (DSC). Unfortunately, though, based on random surveys taken during Coast Guard Auxiliary safety checks, it is suspected that fewer than half the boats with DSC equipped VHF radios are programmed to use this feature. With the press of a single button, the DSC feature digitally sends a distress call to rescue personnel over the Global Maritime Distress Safety System. When your radio is programmed with a Maritime Mobile Service Identity (MMSI) number, the feature transmits to authorities your name, a description of your vessel and an emergency contact person’s information. When the radio is connected to a GPS receiver, it also transmits your vessel’s position. Learn how to program these important safety features in your VHF or hire a marine electronics technician to assist you.

Recreational MMSI numbers typically stay with the radio. When selling a boat, make sure you log in to your MMSI provider’s database and cancel that MMSI registration. This will allow the new boat/radio owner to update the MMSI database with their information. MMSI numbers issued for recreational craft in U.S. waters differ from FCC-issued MMSI numbers to vessels intended for international waters. If you intend on taking your boat into international waters, contact the FCC to obtain the appropriate FCC station license and associated international MMSI number. Some radios allow the original number to be deleted and a second number to be programmed into them. Others require the radio manufacturer or authorized service technician to delete an MMSI number from a radio, allowing a new number to be programmed into it.

Recent Changes

Frequencies in the marine VHF sector are assigned channel numbers for ease of use and identification. Some of those channel numbers had the letters “A” or “B” assigned to them, meaning they are duplex channels with two frequencies available for simultaneous conversation. The letter designation indicated only one of the two available frequencies is used for that channel. The most common a recreational boater would come across is channel 22A, which the Coast Guard uses for official communications and broadcasts. Only the “A” frequencies were used in the United States. Canada and other Countries used the “B” frequency. Some VHF radios have a programming feature allowing you to select whether the channels operate on frequency A or B. The rules governing VHF radio frequencies are issued by the International Telecommunications Union (ITU). As of Jan. 1, 2017, the ITU no longer uses the letter designation following the channel number, but has chosen to make those channels 4-digit channels with either a “10” or a “20” preceding the channel, so channel 22A now becomes 1022 and 22B becomes 2022. The Coast Guard has published a new list of these channel designations on navcen.uscg.gov. VHF manufacturers will eventually change their radios to display the new channel designations.


• Additional information on VHF radio use from the United States Coast Guard can be found at: navcen.uscg.gov
• The United States Power Squadron and BoatUS offer a 2-hour online course in VHF Marine Radio operation.
Information and registration can be found at: boatus.org
• Information regarding Maritime Mobile Service Identity (MMSI) can be found at: mmsiregister.seatow.com
and boatus.com/mmsi