VHF Radio Use: Mayday Calls on Channel 16

Hi seakayakers and kayak fishermen. Welcome to another episode of Notes from a Local, your online audio resource for tips, tools and pointers useful to sea kayakers and kayak fishermen around the world. I'm your host, Dave Williams, broadcasting on the web from Twitter@seakayak.

Today's topic: vhf radio use and some of the problems to expect if you need to make a mayday call.

One of more confusing elements of VHF radio use is the reality of what VHF communications sound like for real. From magazine articles to book chapters, even to audio releases from the Coast Guard auxiliary, there aren't that many resources out there good at helping first-timers get a true sense of the confusion, audio problems, garbled communications and general all-around difficulty that often surround VHF radio use, particularly during mayday calls on channel 16. What we read and see in print and on the web try to make the point that mayday calls should be calm, measured, predictable. The reality is they rarely are.

As an example, let's listen to a recent Coast Guard public affairs video, released with the best of intentions, and accurate in form and protocol, yet which does little if nothing to address the challenges that face the first-time VHF radio users. In the example, the caller explains bare bones elements of making a radio call on VHF radio channel 16:

VHF radio release from US Coast Guard.

Unfortunately, as calm, measured and reassuring as the Petty Officer is while he explains how to make a mayday call on channel 16, the truth and of real-life usage are more often than not an altogether different matter. Mayday calls are frequently encumbered by poor signal reception, caller inexperience, and the difficulties Coast Guard watchstanders actually face while they they're monitoring channel 16.

For example, let's listen in on the mayday call a hypothermic sea kayaker made after capsizing in the in the fast tidal waters of the Sheepscott River in downeast Maine, on the US northeast coast. Notice how garbled, faint and broken by static the paddler's mayday call is:

So here is one difficulty you should expect. Because the Coast Guard uses high-watt output radios connected to any number of high-site antennas placed on mountaintops, first time VHF radio users needs to keep in mind that, although the Coast Guard watchstander's broadcast to you may come in may come in loud and clear, what they hear on their end is likely to be a different matter altogether. Sea kayakers and kayak fishermen in particular, whose handheld radios have small short stocky antennas and are restricted to a maximum of 5 watts of output, have a limited broadcast range. And they are highly to background noise like wind, breaking waves and swell height. Sea kayakers and kayak fishermen's vhf radios used in the cockpit broadcast from a height of three or 4 feet above sea level at best.

What this adds up to: expect that your call faces the high likelihood of being broken up, plague by static and interference, and is pretty likely to present to the Coast Guard watchstander a message that is interesting and indistinct, riddled with static, garbled and just plain difficult to understand.

So, first things first. No matter how dire or desperate your situation, anticipate that the Coast Guard watchstander may have to ask you - more than once -- to repeat and clarify not only your situation but your location and the increasingly less unusual fact that you are in trouble not in the normal and expected recreational boat like a motor- or sailboat, but a sea kayak or fishing kayak.

A second complication most guides to making a mayday call overlook is the caller's fear and panic, let alone confusion. Anyone of these factors can cause a caller to shout into the microphone, hold the VHF radio to close, or turn sideways to the wind - each of which can turn your call into noise-filled gibberish. Shouting into the mic or holding it too close creates an audio distortion referred to as clipping: the volume of your voice overwhelms the radio's microphone's ability to process it. Combine clipping with a first-time VHF radio users sense of urgency and near panic, and you have a VHF radio call that will be near indecipherable on the receiving end, making the call that much more difficult to log, track and understand.

As an example, let's listen to a mayday made in Long Island Sound, on the US east coast. It's made by a scuba diver who has climbed back aboard his boat. He's in an understandable panic. Time is of the essence. His diving companion can't surface; meanwhile, the stream of air bubbles from her air tank, trailing further and further off the stern, show that she's getting swept away in the tide:

Here are basic pointers on using making a mayday call if you or one of your sea kayaking or kayak fishing buddies find yourselves in serious trouble. If you can, maintain enough presence of mind not to scream or shout into the microphone. Don't press the mic to your mouth. Turn away from loud background noises like wind or breaking waves. If your VHF radio is a submersible model, be sure to give the radio a shake before using it. Water gets trapped in the grill of a submersible vhf radio's mic, and will make your voice garble. It's one of the failings of submersible radios: their grills fill with just enough water to make your voice incomprehensible. But above all, be prepared for disconcerting problems: you may be able to hear the Coast Guard perfectly well. But that's because their using both an enormously powerful radio and a very tall antenna. You, on the other hand, are using a tiny radio with a four to six-inch long antenna. Your transmission is not going to be anywhere near as clear as theirs, but you're likely to assume that since you can hear them perfectly well, they can hear you perfectly well. That's not likely to be the case.

Finally, be prepared for a series of potentially vexing questions as the watchstander assembles a case log of your call. He or she will have a lot of questions as to how many people are involved, whether you're wearing lifejackets, what the color of your kayak is, even what the current weather conditions are. These plodding queries can be maddening to the frightened caller, but are a necessity. The watchstander is accountable to a lot personnel in that radio room, including superior officers who have to alert, assemble and dispatch an expensive radio crew. So not only does the watchstander need to know where you are, they need to know who and what to look for, what's the likelihood you can stay above water in a lifejacket, and what the weather is so the search and rescue team can decide what sort of rescue craft to come looking for you. The watchstander may even ask you to count to ten several times in succession - and not because he or she is trying to be funny or cute. Your ten-counts allow the rescue crew to trace your call along a line of bearing, making it easier to pinpoint where you're calling from.

Well that's it for today's episode of Notes from a Local, your online audio resource for tips, tools and pointers useful to sea kayakers and kayak fishermen around the world. I'm Dave Williams, your host, broadcasting over the web from Twitter@seakayak. To learn more about vhf radio use, be sure to follow me on Twitter at sea kayak. Thanks for stopping by. And until next time, see ya 'round.