VHF Radio for Sailors: The Basics

A VHF marine radio is a sailor's main tool for communication and safety at sea — and in an emergency, it is often the fastest way to get help. Unlike a mobile phone, a VHF call is heard by every boat and rescue station in range at once, which is exactly what you want when things go wrong. Here is how it works and how to use it correctly.

What VHF is for

VHF (Very High Frequency) radio is used to talk to other vessels, marinas, and coastguard or rescue authorities; to receive safety and weather broadcasts; and, most importantly, to make distress calls. It works line-of-sight over a range of typically tens of nautical miles, and because it is a shared, monitored system, it is the backbone of safety at sea.

Channel 16 — the distress and calling channel

The channel to know is Channel 16, the international distress, safety and calling channel. Boats and rescue stations monitor it, and it is used to make initial contact and to send emergency calls. Once you have made contact on 16, you normally switch to a working channel to continue talking — keeping 16 clear for emergencies and new calls is a rule everyone follows.

Mayday, Pan-Pan and Sécurité

There are three levels of priority call, and knowing them matters:

• Mayday — grave and imminent danger to a vessel or person: a life-threatening emergency. The highest priority; everyone else stays off the air.
• Pan-Pan (pahn-pahn) — urgency: a serious situation that is not yet life-threatening, such as a breakdown or an injury under control.
• Sécurité (say-cure-ee-tay) — a safety message, such as a navigation or weather warning.

These sit alongside the practical safety kit covered in our guide to offshore safety equipment, and a VHF call is often the first step in a man-overboard or other emergency.

DSC — the distress button

A modern VHF with DSC (Digital Selective Calling) has a dedicated distress button. Press and hold it and the radio sends an automated digital alert — the boat's identity and, if connected to a GPS, its exact position — to every DSC station in range at once. It is the quickest, most reliable way to raise the alarm, and a big reason DSC-equipped VHF is standard offshore.

Using it correctly

Because VHF is a shared safety system, correct use matters: keep transmissions brief, use the right channel, and never misuse the distress channel. In many countries you need an operator's certificate to use a marine VHF, and the radio may need to be licensed to the vessel — check the rules where you sail. For the rest of the language of the sea, see the sailing terms glossary.