Mayday, Pan-Pan, Sécurité
Marine radio has three priority words, all French-rooted and all transmitted on VHF Channel 16: Mayday (from m'aidez — 'help me') for grave and imminent danger to a vessel or life, Pan-Pan (from panne, breakdown) for urgent situations that aren't yet life-threatening, and Sécurité for safety broadcasts like navigation and gale warnings. Each is spoken three times, and choosing the right one is what keeps the distress channel meaning something.
Three words, three priorities
MAYDAY — from the French m'aidez, 'help me' — is reserved for grave and imminent danger to a vessel or a person, requiring immediate assistance: fire, uncontrolled flooding, sinking, person overboard you cannot recover. It commands the channel: all other traffic stops.
PAN-PAN — from panne, a breakdown — declares an urgent situation about the safety of the vessel or someone aboard that does not, yet, need immediate rescue: engine failure while drifting off a shore, a broken rig under control, a crew injury needing medical advice, a vessel overdue. It says 'stand by me and listen' rather than 'come now'. Many Pan-Pans are prevented Maydays — called early, while the mast is dry and the drift is slow.
SÉCURITÉ ('say-cure-ee-tay') is the safety prefix: broadcasts about hazards rather than from victims — coastguard navigation warnings, a drifting container, a tow restricted in its ability to manoeuvre, gale warnings. You'll hear it announced on Channel 16 with the details passed on a working channel.
The discipline matters because priority is a promise: rescuers and every listening vessel calibrate their response to the word. Escalate the moment the situation escalates — a Pan-Pan upgrades to Mayday with one sentence — and downgrade or cancel just as readily.
The Mayday call, and the relay
The full distress call follows a fixed script — fixed precisely so it survives adrenaline: MAYDAY × 3 — THIS IS [vessel] × 3 — MAYDAY [vessel] — position — nature of distress — persons on board — assistance required — other information — OVER. Position comes early and in the marine format, degrees and decimal minutes, latitude then longitude, digit by digit. Our share your location at sea tool reads your GPS and builds this exact script around your live position, including the digit-by-digit readout.
Two variants complete the family. MAYDAY RELAY (spoken three times) is how you pass on someone else's distress — you've heard a Mayday the coastguard may have missed, or you can see a vessel in distress that isn't transmitting; you're not in danger, so you announce that you're relaying. And on DSC-equipped radios, the red-button digital alert precedes the voice call, sending your MMSI and position automatically on Channel 70 — then the voice Mayday follows on 16, because the alert opens the door and the voice tells rescuers what's wrong.
Controlled silence: seelonce and prudonce
Once a Mayday is running, Channel 16 belongs to it. The controlling station — usually the coastguard — can order interfering traffic off with “SEELONCE MAYDAY” (the anglicized French silence), and any station may protect the distress working with it. When the crisis eases enough for restricted normal traffic, the controller announces “PRU-DONCE” (prudence); when the distress traffic has ended entirely: “SEELONCE FEENEE” (silence fini). You don't need to transmit any of these as a small-craft skipper — you need to recognize them, and above all to obey the first one instantly.
If you hear a Mayday and the coastguard answers, stay off the air, write down what you heard (position especially) and keep listening — you may become the relay if contact is lost. If nobody answers a Mayday you can hear, answering it yourself and relaying is not merely allowed; rendering assistance is one of the sea's oldest legal obligations.
Saying it so it lands
Priority words work only as spoken sounds on a noisy channel, which is why every element of the system is phonetic: niner for 9, decimal for the point, the NATO alphabet for vessel names (Sierra-Echo-Alfa Delta-Romeo-India-Foxtrot-Tango survives static that 'Sea Drift' doesn't). Speak slowly — slower than feels natural — keep the mic a few centimetres from your mouth, and release the button after OVER so the answer can reach you. The full alphabet and figure pronunciations, plus the position readout practice, live on the at-sea location page.
And a land-side footnote: the priorities are marine (and aviation) grammar, but the underlying idea — a fixed script, position first, digits spoken singly — is exactly what emergency call-takers want on a phone too. The shore version of this page is share your location in an emergency.