Why a VHF Radio Is Non-Negotiable
Of all the safety equipment you carry on a boat, a marine VHF (Very High Frequency) radio is arguably the most important. Unlike a mobile phone, a VHF radio works at sea regardless of cellular coverage, allows you to communicate with all nearby vessels simultaneously on distress channels, and connects you directly to the coastguard. In an emergency — fire, flooding, medical crisis — a VHF radio can save your life in ways no other device can replicate.
Fixed Mount vs. Handheld: Which Do You Need?
There are two main types of marine VHF radios, each suited to different situations:
| Feature | Fixed Mount | Handheld |
|---|---|---|
| Transmit Power | 25 watts (maximum) | 5–6 watts |
| Range | Up to 20+ nautical miles | 3–5 nautical miles |
| DSC Capability | Yes (connects to GPS) | Some models |
| Power Source | Boat's electrical system | Rechargeable battery |
| Best For | Cruising, offshore sailing | Backup, dinghy, kayak |
For any boat venturing offshore or on extended coastal passages, a fixed-mount VHF with DSC (Digital Selective Calling) capability is strongly recommended. A handheld radio makes an excellent backup and is essential for tenders and dinghies.
Key Channels to Know
VHF marine radio operates on internationally standardized channels. The most important ones to know are:
- Channel 16: The international distress, safety, and calling channel. All vessels must monitor this channel at all times when underway. Never use it for routine communications.
- Channel 70: Used exclusively for DSC digital distress signals. Do not use for voice communication.
- Channel 9 (US) / Channel 67 (UK): Secondary calling channel used in some regions to reduce traffic on Channel 16.
- Channels 68, 69, 71, 72, 78: Recreational and working channels for inter-vessel communication after initial contact on Channel 16.
- Weather channels (WX1–WX10, US): Broadcast continuous NOAA weather forecasts — essential for passage planning.
Understanding Digital Selective Calling (DSC)
DSC is a feature on Class D and higher VHF radios that allows you to send an automated digital distress signal at the press of a dedicated button. When connected to a GPS, the distress signal includes your vessel's MMSI number (Maritime Mobile Service Identity) and your exact position — giving rescue services everything they need to find you quickly.
To use DSC properly, you must register your radio and obtain an MMSI number from your national maritime authority (e.g., FCC in the US, Ofcom in the UK). This is free in most countries and takes only a few minutes online.
How to Make a Mayday Call
In a life-threatening emergency, follow this procedure on Channel 16:
- Say "MAYDAY MAYDAY MAYDAY"
- Say "This is [vessel name] [vessel name] [vessel name]"
- Say "MAYDAY [vessel name]"
- State your position (GPS coordinates or bearing from a known point)
- Describe the nature of the distress
- State the number of persons on board
- Give any other relevant information
- Say "OVER" and await a response
Top Brands to Consider
Several manufacturers produce reliable marine VHF radios. Commonly trusted brands include Standard Horizon, Icom, and Garmin. When evaluating models, look for IPX7 or JIS7 waterproof ratings, DSC class D certification, GPS connectivity, and a loud hailer function for larger vessels.
Whichever radio you choose, practice using it before you need it in an emergency. Familiarity with your equipment under pressure is what turns good gear into real safety.