The US Coast Guard crackled over VHF Channel 16 requesting the commercial passenger fishing vessel Victory to help with a radio relay between Coast Guard Base Los Angeles and a disabled pleasure boat, the 25-foot Fin Fun (the name has been changed to protect privacy), on the backside of Santa Catalina Island.
The captain of the Victory agreed to serve as an intermediary in a crucial VHF conversation that would quickly switch over to Channel 22 Alpha, clearing Channel 16 for other traffic, and allowing the USCG to assess the situation and eventually arrange towing assistance for Fin Fun.
How exactly the USCG became initially aware of Fin Fun’s troubles and location remains unknown. But what was certain was the inability of the USCG and Fin Fun to conduct ongoing communication directly via VHF because a mountainous landmass stood between them. USCG shore-station antennas can boom out great distances, but not over Catalina Island, which rises to nearly 2,100 feet in elevation in places.
This brings us to the concept of a VHF relay—in this case, the reason Victory could talk to both Fin Fun and the USCG station laid in its position a mile or two off the east end of Catalina Island. This put Victory within line of sight between both the base and Fin Fun, as depicted in the illustrated map.
On top of this, Victory—being a 75-foot vessel with a relatively high wheelhouse and tall antennas of its own—possesses a greater VHF range than most recreational vessels, at least enough to relay messages to and from US Coast Guard Base Los Angeles, some 32.5 miles away.
So, how did the Coast Guard even have a clue that Victory was in a good position to serve as a VHF relay? The answer is Automatic Identification System, which broadcasts and receives position data via VHF. Being a commercial passenger vessel exceeding 65 feet in length, Victory is required by federal Maritime Transportation Security Act regulations to be equipped with and operate a Class-A AIS transceiver at all times while at sea. With AIS, the USCG could clearly see that Victory was sitting in the best position to help out.
What seamanship lessons can we learn from this story? First, let’s imagine things from Fin Fun’s point of view: behind a landmass or simply out of range, and suffering mechanical trouble that calls for assistance. It’s not a full-blown emergency, but there’s no getting home without help. Sitting outside cell coverage, VHF calls for help on Channel 16 go unanswered.
If this is you and you have AIS, try to identify a vessel in the general area and/or closer to shore that might be in a position to serve as a relay. Tall commercial shipping vessels such as freighters and tankers will, as alluded to earlier, have greater VHF range and so serve as the best relays. Hail the vessel on Channel 16. If you reach them and establish a line of communication, ask if they will serve as a relay.
Without an AIS, try putting out a general request over Channel 16, asking if any vessel hearing your message would be willing serve as a relay.
Whether broadcasting a general or targeted request, once you establish communication, you will need to find out if the responding vessel itself can effectively communicate with shore stations. If not, you will need to start over. If the responding vessel can indeed serve as a VHF relay, you’re in business.
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From the relay vessel’s point of view, always be monitoring Channel 16, and if a VHF request comes in about serving as a relay, be ready to respond, and stay with the communication process to its successful conclusion and/or when the responding agency releases you. That means not only staying by the VHF radio to listen for and relay transmissions, but potentially remaining on station as well.
The Coast Guard or other agency will request that all parties switch to another channel, such as 22 Alpha. Once everyone is synced up, keep all communication concise and to the point.
