VHF Marine Radio Basics & Channel 16

Printable checklist: Launch day

A VHF-FM marine radio is the standard way recreational boaters send distress alerts and talk to the Coast Guard, other boats, bridges, locks and marinas. Discover Boating (NMMA) calls it critical safety gear that should be aboard every powerboat; the U.S. Coast Guard's Boater's Guide to the Federal Requirements for Recreational Boats recommends always carrying a means of sending distress alerts and communicating with other boats, and names a VHF marine radio as the most common. The Coast Guard also says a cellular phone is not a substitute for the maritime radio distress and safety systems recognized by the FCC—though a phone can still be useful as an added layer.

We do not invent radio range in miles, channel lists beyond what official pages state, or a blanket "you must always carry VHF" rule for every recreational vessel. Carriage and licensing depend on vessel class and where you boat—confirm with the FCC ship-radio pages, the Coast Guard Boaters Guide and State Rules. Federal required carriage gear by length (PFDs, extinguishers, visual distress signals and the rest) is in required safety equipment by length; navigation light patterns and day shapes are in navigation lights and day shapes. VHF is recommended communications gear, not a substitute for that list.

Channel 16: distress, safety and calling

The FCC designates VHF Channel 16 (156.8 MHz) as the channel for distress, safety and calling—use it to get another station's attention or in an emergency. The Coast Guard's May 2024 Jacksonville release restates the same point: Channel 16 is the national distress, safety and calling frequency. After you make contact on 16, change immediately to a working channel that fits the type of message (FCC ship-radio operations; Discover Boating).

Keep chats off Channel 16. Discover Boating's etiquette page: Channel 16 is for hailing and distress—once you contact another vessel, switch to another frequency. The Coast Guard Boaters Guide: Channel 16 should not be used for general conversation or radio checks.

Channel 9 (156.45 MHz) is the FCC's boater calling channel for recreational (noncommercial) vessels, set up at the Coast Guard's request to relieve congestion on 16. Call other recreational boaters on 9 when you can; keep calling the Coast Guard and commercial facilities on 16 (USCG Boaters Guide).

Radio checks (not on Channel 16)

The Coast Guard urges mariners not to run radio checks on Channel 16. Use Channel 9 or another similar channel used in your area (USCG May 2024 release). Discover Boating's VHF marine-radios page matches that: conduct radio checks on Channel 9, not 16. Discover Boating's how-to page also lists open working channels for a check (68, 69, 71, 72 and 78A), at the one-watt setting, saying "radio check" three times with your boat name and location.

False or accidental distress traffic on 16 can delay real help. The Coast Guard treats distress broadcasts as legitimate until proven otherwise; if you accidentally broadcast a distress alert on Channel 16, contact your local Coast Guard sector immediately (USCG May 2024). Knowingly transmitting false distress calls is a federal crime under 18 U.S.C. § 1038, with criminal and civil penalties (USCG May 2024). The Boaters Guide separately states it is unlawful to intentionally transmit a false distress alert, or to unintentionally transmit one without canceling it.

How to hail another boat (voice)

FCC ship-radio operations (summarized):

  • Maintain a watch. When underway, keep the radio on and tuned to Channel 16 except while you are using it for a message. The Boaters Guide adds that recreational vessels that voluntarily carry a radio (for example, under 20 meters / 65.6 ft and not otherwise required to carry one) must maintain a watch on Channel 16 or Channel 9 whenever the radio is on and not in use for a conversation.
  • Power. Try one watt first if the station is within a few miles; switch to higher power only if needed. FCC equipment rules: ship-station power in the 156–162 MHz band must not exceed 25 watts (portables excepted from that ceiling), and the radio must be able to drop to one watt or less. We do not publish invented "miles of range."
  • Calling limits. Do not call the same station for more than 30 seconds. If no reply, wait at least two minutes before calling again. After three calling periods, wait at least 15 minutes.
  • Identify in English with your FCC call sign, ship name, state registration number or official number at the beginning and end of each message.
  • After contact on 16, switch to a ship-to-ship working channel; when finished, identify and return to 16.

Discover Boating's hail pattern: say the other boat's name twice, then your boat name and "over"; agree on an open channel; keep operational messages short (weather and boat needs are fine—sports chatter is not).

Distress, urgency and safety voice calls

The FCC lists three spoken international emergency signals (say the signal three times before the message; these take priority over routine traffic):

Signal Meaning (FCC)
MAYDAY Grave and imminent danger; immediate assistance requested
PAN PAN Safety of the ship or a person is in jeopardy
SECURITÉ Safety of navigation or important weather warnings

Voice MAYDAY on Channel 16 (FCC marine distress procedure—speak slowly, clearly, calmly):

  1. Radio on; select Channel 16.
  2. "MAYDAY — MAYDAY — MAYDAY."
  3. "THIS IS" + your ship ID.
  4. "MAYDAY" + your ship name.
  5. Position (landmarks, lat/long, bearing and distance—state true or magnetic).
  6. Nature of distress; number of persons aboard and any injuries.
  7. Seaworthiness estimate; brief ship description (size, type, color).
  8. "I will be listening on Channel 16." End with "THIS IS [name/call sign] OVER," then listen. Repeat if no answer.

Discover Boating: full power on 16 for a life-threatening emergency; use pan-pan when the situation is serious but not life-threatening. Do not say "mayday" unless there is a real emergency that threatens life or property (Discover Boating VHF marine radios; etiquette page—false distress is against the law; keep kids off the radio).

The Boaters Guide also publishes a step-by-step Channel 16 MAYDAY script (vessel name three times, registration/call sign, position, persons, nature of distress, assistance needed, "OVER"). Prefer the live Coast Guard or FCC wording over memory when you can.

DSC and MMSI (high level)

Digital Selective Calling (DSC) lets a properly set-up radio send a formatted distress alert (and other call types) to the Coast Guard and DSC-equipped stations. The Coast Guard Boaters Guide and Rescue 21 pages: with GPS connected and an MMSI programmed, pressing the red DSC emergency button (about five seconds in the Boaters Guide) can send identity and position; after acknowledgement the radio should shift to Channel 16 for voice. Discover Boating: DSC needs an internal GPS or a link to a chart plotter/GPS—many owners never finish that link.

An MMSI is a nine-digit Maritime Mobile Service Identity used by DSC (and AIS). The FCC: if your marine radio has DSC, you must obtain an MMSI and program it before you transmit; each vessel needs only one. High-level path from official pages (confirm current steps on those pages—we do not invent signup flows):

  • No FCC ship-station license required (typical domestic voluntary recreational boat): domestic MMSI from FCC-authorized private registrants such as BoatUS, U.S. Power Squadrons / America's Boating Club, or Shine Micro (USCG Boaters Guide; FCC MMSI and equipment pages). Rescue 21 for Boaters also points boaters to BoatUS and Sea Tow MMSI programs certified by the FCC and Coast Guard.
  • FCC license required (see licensing below): MMSI is issued in the FCC ULS licensing process.

FCC: do not send a DSC distress call as a test—severe penalties can apply for false alerts that are not canceled. The Boaters Guide: if you inadvertently send a false DSC alert, reset the equipment, then broadcast a cancel on the associated distress/safety frequency with ship name, call sign, time, MMSI. Coast Guard Rescue 21 and NAVCEN publish more on DSC testing and alerts—confirm there before you press anything.

We do not invent wattage "for DSC," offshore range claims or a full channel-70 how-to beyond: FCC lists Channel 70 as digital selective calling only.

Fixed-mount vs handheld

Discover Boating: a fixed-mount VHF runs on the boat's electrical system; a handheld is battery-powered and can still work if the house battery dies or you abandon ship—many float and are waterproof, so a handheld is a useful backup to a fixed set. FCC: a special marine utility station license is required to operate a handheld marine VHF from land (a ship station license alone is not enough).

Licensing (voluntary recreational boats)

Per the FCC ship-radio licensing page and the USCG Boaters Guide:

  • Most recreational ("voluntary") vessels operating domestically do not need an FCC ship-station license to use marine VHF, radar or EPIRBs, and do not need an individual operator license for VHF-only use when they are not docking in foreign ports or communicating with foreign stations.
  • You must still follow FCC operating procedures and courtesies. Identify with vessel name or registration number if you have no call sign.
  • An FCC license (and typically a restricted radiotelephone operator permit) is needed for foreign ports / foreign stations, and for certain vessel classes the FCC lists as outside "voluntary ships" (for example, power-driven ships over 20 meters on navigable waterways—see the FCC list; the Boaters Guide notes power-driven vessels more than 65 feet / 20 meters and vessels on an international voyage among those that may need licensing).

Confirm the live FCC pages for your boat. State equipment and education rules still sit in State Rules and your state page.

What not to transmit

FCC prohibited communications include:

  • False distress or emergency messages
  • Messages with obscene, indecent or profane words or meaning
  • General calls on Channel 16 except in an emergency or when testing your radio
  • Transmitting when the ship is on land (for example, on a trailer)

Discover Boating: no foul language; supervise children; do not treat the radio as a toy; keep transmissions short and listen before you talk.

Before you leave the dock

Channel 16 is also the call when simple troubleshooting fails—see boat troubleshooting and when to call a pro.

Radio and communications gear belong next to the rest of your launch routine—printable Launch Day checklist, first-season checklist, and cold-water preparedness in cold-water safety (Alaska) (NWS lists VHF alongside EPIRB/PLB as a way to call for help). If anyone shows CO-poisoning symptoms (often mistaken for seasickness), get them to fresh air and use Channel 16 for urgent help—see carbon monoxide safety on boats. The same Channel 16 call applies if you cannot control a fire—see boat fire extinguishers and fire safety. Book a free Vessel Safety Check with the Coast Guard Auxiliary; Rescue 21 notes examiners can also help confirm GPS-to-VHF DSC wiring. Budget radios and related gear in the True Cost tool if you are still outfitting the boat.

Pyrotechnic flares, orange distress flags and electric distress lights (coastal carriage, expiration and legal use) are covered separately in visual distress signals and flares—radio does not replace required VDS where Subpart C applies. Satellite EPIRB and PLB 406 MHz beacons (when radio may not reach anyone, NOAA registration, vs DSC) are in EPIRB, PLB and distress beacons. AIS (being seen by other traffic vs calling for help) is covered in AIS basics for recreational boaters. Radar (detecting vessels and hazards that may not transmit AIS) is in radar basics for recreational boaters. Chartplotter / GPS (position on a chart and the GPS feed DSC needs) is in chartplotter / GPS basics for recreational boaters.

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