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VHF Marine Radios

by Val Wann

VHF Radio - What is it?

VHF radio

When a boater talks about "carrying/using a VHF" they're usually referring to a portable 2-way radio that operates on frequencies set aside specifically for marine use. Among kayakers these are usually handheld "walkie talkie" units. They can be used for communication between boats, from boats to harbor masters or traffic control, to make ship-to-shore "telephone" calls, and most especially to call for help in an emergency. Most marine radios can also receive weather information broadcast by the National Weather Service (NWS)—a handy reference that reduces your chance of being surprised by weather changes.

What is it NOT?

VHF radio

A marine radio is not intended for all types of communication; it is only to be used between boats, or between a boat and specific shore facilities such as the Coast Guard, traffic control, or harbor master. It is not supposed to be used to talk to friends on shore. Informal chit-chat—such as dominated the old CB (Citizens Band) radios—is discouraged. If you only want a radio to talk amongst your small group, consider an FRS (Family Radio Service) unit - these are relatively inexpensive low-power FM radios that have fewer restrictions on their use. Most importantly remember that radios broadcast; anyone in range can listen in to your conversation: it's not at all private.


VHF radio frequencies do not "bend" over the curve of the Earth or around obstacles. There must be a clear line of sight between your radio and the receiving antenna. In the Bay Area and other high-traffic urban areas, the Coast Guard will have antennas on high mountains or towers so they can communicate for many miles. However if you're sitting in your little kayak taking shelter beneath a rocky bluff or headland, your signal may be blocked. It might be necessary to either move farther off shore or climb a hill to be able to make contact. Remember that marine radios are not normally for use on land!

Radio or Cell Phone?

VHF radio

In urban areas where there is good coverage, a cell phone can be an excellent option to call 911 for emergency assistance. It also provides more private communication if you are calling home or making reservations at a boat-in restaurant. Just be sure to keep it in a waterproof case! However a phone cannot be used to broadcast a call for help from anyone nearby, nor can you use it to monitor vessel traffic or weather broadcasts. And if you need to talk to that commercial ferry that's about to run you over, don't count on Directory Assistance.


The FCC does not currently require "operators of recreational vessels" to have a license to use a handheld VHF marine radio.

Usage tips

  • Operation—While the operation of VHF radios will vary from model to model, they all have the same basic functions. When you turn the unit on, you will hear any messages that are being transmitted on that channel. After setting the volume control, adjust the squelch. The squelch regulates which signals the unit will receive: turned to maximium, only the very strongest signals will get through; set to minimum, all signals will get through: noise, static, weak signals, strong signals. The scan function will start the unit scanning all channels for transmissions; when it receives an incoming message it will pause and monitor that channel. When transmission stops, the unit will continue scanning.
  • Identify yourself—Normally a boater would give the boat's name and/or registration number when calling on the radio. Many kayakers do not name their boats, and fortunately California does not yet require registration numbers on small unpowered craft. You should still give some identifier when you call, such as "Yellow Kayak near Angel Island", "BASK Pod #1", or "Kayak John". When transmitting, first identify the person you are calling then identify yourself. (Example: "BASK 1, this is BASK 2. Can you wait until our pod catches up? Over." Reply: "BASK 2, this is BASK 1. We need to punch on through this tide rip. We'll wait for you in the calmer water on the other side. Over." Reply: "BASK 1, BASK 2. Roger. See you there. Out.")
  • Roger, Over and Out—Saying "Roger" is a confirmation that you have received and understood what another person has said. Since VHF radios cannot transmit and receive simultaneously, when you finish speaking, say "Over". This lets the other person know you are releasing the microphone button on your radio and are now ready to receive their reply. When the conversation is finished and you do not expect any further reply, say "Out". Although they do it in the movies, do not say "Over and Out"—it sends a mixed message.
  • Speak clearly—Noise from wind, waves, boat engines etc. can make your words difficult to understand. Speak slowly and clearly with the microphone near but not right against your mouth. When giving numbers, speak each digit separately (say "one-two-zero" rather than "a hundred and twenty"). Since 5 and 9 sound pretty much alike, say "Niner" for 9 but keep "Five" as one syllable. If you have to spell a word or name, consider using the International Phonetic Alphabet.
  • Ship-to-shore telephone—If you want to make a ship-to-shore telephone call, contact the Marine Operator who will connect you to a phone line. There may be a fee for this service. Remember it's not private!
  • Watch your language—This is "public" radio, after all. The "seven dirty words you can't say on the air" still apply. The FCC can fine you for profanity.

Distress calls

Anyone who has a marine radio turned on, and who is not currently engaged in a conversation on another channel, is required to monitor the emergency channel 16. If you get into serious trouble and need to call for help, make the call on that channel.

If you think the situation is life-threatening, it's time to use the International Distress Signal "MAYDAY". Here's how:

  1. Be sure your radio is set to channel 16.
  2. Press the Transmit (microphone) button and say "MAYDAY" three times.
  3. Say "THIS IS" one time.
  4. Give your identification three times.
  5. Repeat "MAYDAY".
  6. Give your location as precisely as you can - either GPS coordinates or bearing and distance (specify magnetic or true if you can be that precise) from a known landmark. Give the best information you can of your course and speed.
  7. State the nature of your emergency (sinking, hypothermic, etc).
  8. State the assistance required.
  9. Give any other information that could help rescuers find/identify/assist you (color of boat, color of PFD, number of people needing assistance, etc.
  10. Say "OVER" and release the mic button. If you do not get a response in a minute or so, repeat the call. Continue to monitor the radio if possible and be ready to reply when a response comes.


"Mayday, mayday, mayday, this is Kayakers in Golden Gate, Kayakers in Golden Gate, Kayakers in Golden Gate. Mayday. We are about a quarter-mile southwest of the north tower of the Golden Gate Bridge. Bearing from us to the north tower is zero-four-zero degrees magnetic. We are being carried westward by tide and wind approximately 2 knots. One member of our group is unconscious and may have suffered a heart attack. We need immediate pickup and transportation to a hospital for one person. We are a group of 4 kayaks - two are red, one is white, one is yellow. We are rafted together and have a yellow paddle blade held up to make us easier to see. Over." It's worthwhile to rehearse a distress call in your mind or among friends (not using a radio!) so if you ever really need to call for help you will do so in a clear, organized, and (relatively) calm manner.

Lesser Degrees of Distress

VHF radio

If you need to make an emergency call for a situation that is not immediately life-threatening, the International Urgency Signal is "PAN-PAN" (pronounced pahn-pahn, sort of like pawn-pawn). Use the same basic format as a MAYDAY call.

If there is a situation regarding public safety (such as a ship that has broken it's mooring and is drifting into a busy shipping lane), use the International Safety Signal "SECURITY" (pronounced say-cure-i-tay). Again, use the same basic format as for a MAYDAY.

If you are not yet in an emergency but think things might get more difficult, consider calling the Coast Guard and advising them of your situation and location. If you make it to shelter OK, call them immediately and tell them so. If you end up having big problems, they will at least have an idea where to start looking for you.

Don't Cry Wolf

Mayday, Pan-Pan, and Security calls take immediate priority over all other radio traffic. Do not use these signals carelessly. Also remember that if you make a distress call, Emergency Services are obligated to devote their resources to finding and helping you. If they lose contact with you, they will conduct a search. If it's not really an emergency, this can tie up people and equipment that might be needed elsewhere to save someone's life. By all means call for help if you really need it, but if you later manage to get yourself out of trouble be sure to let Emergency Services know so they don't continue looking for you.

If You Hear a Distress Call

In a kayak, you are very limited in the amount of assistance you can provide another vessel. Remember your first obligation is to avoid getting yourself in trouble and requiring an additional rescue. If you hear a distress call, wait a few moments to see if the Coast Guard or larger vessel responds. If not, the boat in distress may not be able to reach the Coast Guard antenna. You might be in a position to relay messages to the CG or others that can affect a rescue. If there is something useful you can actually do, volunteer to help. Remember to keep conversation clear and as brief as possible. If you can not help, stay off the radio and out of the way.

"Hailing Frequencies Open"

VHF radio

Since everyone with a radio turned on is supposed to be monitoring Channel 16, it is permitted to use this channel to initiate contact with other boaters. Be sure to keep conversation to a minimum—just get their attention and agree upon another non-commercial channel to switch to.

In some areas, particularly Northeast/Great Lakes, use of Channel 16 has become so heavy that the Coast Guard has requested boaters to begin using Channel 9 for hailing and contact. Ch. 9 is also used by the Coast Guard to broadcast urgent weather and safety advisories, thus many vessels monitor this channel regularly.

Another alternate contact channel for non-commercial boaters is Channel 6. This channel is also used for "inter-ship safety" communications and so is frequently monitored.

Other Useful Channels

In addition to Channels 6 & 9 for hailing and safety broadcasts, and Channel 16 for hailing and emergencies, it might be useful to monitor the local Vessel Traffic System if you are in an area with lots of commercial shipping. In the SF Bay Area, VTS uses Channel 14.

The non-commercial channels usable by kayakers are: 68, 69, 71, 72, & 78A. When you gather at the put-in for a pre-trip briefing, agree on a communications channel and then do a radio check. Many radios have a dual-scan capability and this allows you to monitor your chosen channel (say 69) plus the emergency Channel 16. A link to the complete list of channels is given in the Glossary.

Where Will You Carry It?

VHF radio

There are radios are small enough to fit into some PFD pockets, although the antenna may stick out. Some people have "Dirty Harry" style shoulder holsters that comfortably carry larger radios. A belt pouch may be another solution. If you have a pocket in your spray skirt, you may be able to fit the radio in that. Just be aware it may get interfere with, or get banged about during, a rough water re-entry.

If you keep the radio in your cockpit, in a day hatch, or strapped to your deck, you may not have the radio with you if you get separated from your boat - one circumstance in which a radio could be very useful.

Once you can find a convenient place to carry your radio, you'll be more likely to carry it on every paddle and will thus have it when needed.

Speaking of when it is needed, remember that listening to various chatter while paddling will use up your batteries. If you keep your radio off, then you will have the full reserve of the battery should be become necessary to use the radio in a real emergency.

Features to consider when buying

There are lots of radio models on the market, and good marine supply stores will have several different ones in stock. Most radios offered by a reputable dealer will provide basic and emergency communications. So which one should you buy? In general, smaller units with more features are more expensive than bulkier or "bare bones" radios. Here are some of the choices you can make:

VHF radio

  • Size—Where will you be carrying the radio? Is the smallest one still too big to fit in your PFD pocket? If so, it may not be worth spending the extra money for a compact unit. Will you be putting it in a dry pouch? If so, see what pouch sizes are available & make sure the radio fits.
  • "Waterproof" vs. "Submersible"—A radio rated as "Submersible" means it is designed to survive repeated dunkings and still operate. Some, however, are very hard to hear when the speaker is wet - you need to dry it out before you can really use it. And just because it's rated submersible does not mean that it will float! If you don't want to use a dry bag, use a lanyard to attach it to your PFD.
    "Waterproof" radios may function OK if they get splashed occasionally, but don't count on it continuing to work if it gets really wet (which it will in a kayak!) Best to put it in a dry bag for extra security. If the radio is not rated as Waterproof or Submersible, then it should not be allowed to get wet at all. Be sure to keep it in a good dry bag. This could be your last-resort tool in an emergency; you want to be able to count on it working when you need it!
  • Button vs. knob controls—Remember you may be using this radio with cold hands, with gloves on, and possibly in a dry bag. Big buttons are easiest to use. Small buttons may prove more frustrating than knobs. Some dry bags have a "finger glove" that allows you to get a finger into the bag to operate knobs on top of the radio. If possible, try operating the radio in a dry bag before buying.
  • Power output adjustment—Some radios allow you to choose between two power settings (typically 1 watt vs. 5 watt) for transmitting. A lower setting may slightly reduce your transmit range, but it will draw less power from the battery. Having the option of choosing allows you to conserve battery life when making short range calls, yet you have the higher power available if needed. Remember that most of the time in a kayak your range is probably going to be limited by the height of your antenna and line-of-sight rather than the power output of the transmitter, so you will rarely get much advantage from the higher power setting. Note that this power choice only effects how quickly the battery is drained while transmitting; not when the unit is switched on for reception only.
  • Multiple channel operation—Some radios have "scanner" functions or at least allow you to monitor two channels simultaneously. Usually you will monitor the emergency/hailing channel (16), and be able to converse with your pod mates on another channel. In areas with commercial shipping, it can also be helpful to monitor traffic control channels. Scanning ALL channels constantly can be frustrating; the better units allow you to program only selected channels to scan amongst.
  • Rechargeable vs. replaceable batteries—Rechargeable batteries are certainly more environmentally friendly than constantly throwing away disposables. On the other hand, if you are on an extended expedition and do not have access to electrical power to recharge your batteries, the radio may be useless by the end of the trip. You can always carry spare disposable batteries. Some radios have the option of using either a rechargeable or disposable batteries, so you can have the best of both worlds. See the Glossary for more information on battery types.
  • Weather broadcast monitoring—Most handheld VHFs these days also can receive weather information broadcast by the NWS. Although you should not consider any forecast to be 100% accurate for the area you are paddling, this regional information may help keep you from being surprised by a nasty change in the weather.


Batteries—Note that all spent batteries are regarded as hazardous waste and should be disposed of accordingly.

  • NiCad = Nickel-Cadmium batteries. One of the most common types of rechargeable batteries. For best results, always drain these batteries completely then recharge completely before use. NiCads are the worst consumer batteries in terms of environmental hazards. Spent NiCad batteries require treatment as harzardous waste and they should be disposed of at a proper recycling center.
  • NiMH = Nickel-Metal Hydride batteries. A newer form of rechargeable battery that is a bit more reliable than NiCad
  • Li-Ion = Lithium Ion batteries. Compact, high power, easily rechargeable, and expensive batteries used in the smallest radios.
  • Alkaline = standard "disposable" batteries available in most stores

Channel—A specific frequency set. Two radios tuned to the same channel can communicate together. Radios tuned to different channels cannot. Here is a listing of channel assignments from a commercial site:

Federal Communications Commission (FCC)—The government agency that regulates radio usage.

International Phonetic Alphabet—Standardized words to represent letters, useful when noise is drowning out part of what you are saying.

Submersible—Radio should continue to operate even after being dunked, although it may need to dry out before it works right.

Squelch—Adjusts the sensitivity of the receiver so you don't have to listen to static - just the strong signals. Some radios have a knob for this adjustment, some have automatic electronic circuits.

VHF—Very High Frequency. Refers to the FM (Frequency Modulation) frequency range in which the radio operates. Marine radio channels are all between about 156 MHz and 162 MHz.

Waterproof—Radio should continue working after getting splashed, but don't count on it.


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